a dive under Japanese waters


As with most things in Japan, local diving has developped its own peculiarities in terms of etiquette, diving style and culture, but also other more practical aspects that we’ll go over in these pages.

Japanese diving has a long tradition, developed in partial isolation mostly because of the language barrier.
This hold both within the Japanese archipelago and abroad, where Japanese divers usually prefer diving in structures offering service in Japanese, and operating within Japanese cultural codes.
This relative isolation has helped develop and reinforce trends and practices which can be a little surprising at times, some of which we will briefly present in the pages of this website.

And yet Japan is not alone in this.
Similarly, the most commonly encountered diving culture in France – a primarily club-based diving culture, operating under strict standards of CMAS-affiliated French federations and of the legally binding French Sports Law is sometimes refered to as the French School of diving, with a touch of pride not unlike the one found in references to guiding divers Japanese-style.
Both diving cultures do present somewhat similar profiles, set within their own frames of reference, and can be equally surprising when seen from outside!

  • Diving agencies in Japan
  • A specific legal framework
  • Diving style
  • Dive operators
  • Payment and Pricing
  • Equipment and rental options
  • Liability release and medical certificates
  • Insurance
  • Diving certification cards and levels

Diving agencies in Japan

As in most Asian countries, Japanese diving is primarily done under the influence of the RSTC framework.
The RSTC, or WRSTC, stands for World Recreational Scuba Training Council, an organisation created in 1999 in the USA, aiming to establish common minimum recreational diving training standards shared by all affiliated scuba diving certification agencies.

Most of the affiliated agencies are of North American origin and commercially motivated.
They include associations such as PADI, SSI, SDI or NAUI, sharing unified training standards and certification levels (Open Water Diver, Advanced Open Water Diver, Rescue Diver, Divemaster, Instructor etc…).

While these agencies only regulate actual diver training, the influence of their training standards shapes way non-training, recreational “fun dives” are organised.

This is not to say that Japan does not have other structures – there are a number of CMAS-affiliated federations in Japan, clubs and structures operating with the often more demanding CMAS standards for diver levels (CMAS One Star* Diver, Two Star*, Three Star ***/ Diver Leader, etc…).
There is also a marked BSAC presence (British Sub-Aqua Club, which operates on standards similar to those of the CMAS, of which it was formerly a member), along with agencies focusing on technical diving.
Yet the most commonly encountered standards and, subsequent dive-style will be based on RSTC training standards, which can also be partially attributed to the historical links between Japan and the United-States, where the RSTC framework was developed.


Looking at World Recreation Scuba Training Council / RSTC affiliated agencies, PADI is now the market leader in the country.
PADI Asia-Pacific’s Japan branch has issued more than 2 million certifications in the country since the first international office was established in Tōkyō in 1979, which gives it the second place as country with the most PADI-certified divers in the world.

However, the first non-CMAS agency firmly implanted in the country was actually the NAUI, which established an early base in Japan, a few years after the agency was founded in 1960.
A NAUI ICC ( Instructor Certification Course) was held in Japan in 1970, and served as the first non-CMAS scuba instructional program in the country, almost a decade before PADI arrived on the Japanese market. 
Because of the history, NAUI is still well represented in Japan, especially amongst older divers and in Okinawa.

As elsewhere in Asia, SSI dive-shop affiliations are on the rise, as is the SDI/TDI presence in the country (appreciated for its handy links to the TDI tech diving curriculum)

Japan also has a number CMAS affiliated diving federations, including:

the Japan-CMAS (JCS),
the CMAS Instructor Association Japan (JCIA),
the Japan Educational Facilities Federation  (JEFF),
the Kansai Sports Diving Federation Japan  (KD Japan),
the Marine Techno Educational System Diving Division  (MTES)

and the Japan Underwater Sports Federation  (JUSF), focused on underwater sports activities.

Sharing similar standards to those of CMAS (of once it was once a member), the BSAC also has an active and growing presence in Japan.

On the technical diving front, other then the previously RSTC agencies’ tech diving curriculums and previously mentioned TDI, you’ll find some GUE and IANTD communities and training options.

On the freediving side of the underwater world, other than the freediving curriculums now offered by all RSTC scuba-agencies, you’ll find an AIDA federation, the Japan Apnea Society (JAS). There is also an Apnea Academy affiliated operations or the freediving section of the CMAS affiliated Japanese UW sports federation for instance, and freediving will no doubt be growing in Japan as it is elsewhere (and let’s not forget that Japan has its own professional freediving tradition…).

Major Japanese scuba diving associations also include the Japan Scuba Diving Association, as well as the Japan Leisure Diving Association JLDA.

On the professional side, Japan has an association for licenced professional divers (sensuishi), the Japan Dive Association (JDA), and also the Japan Professional Scuba Diving Instructors Association (JP), which also hosts the Japan Snorkelling Federation.

affiliated schools also issue their own diver certification cards, following RSTC level structures.
Another structure issueing certification is the Stars Net-diver School network, that issue certification cards following either RTSC or CMAS level structures.

Beyond agencies, other diving related initiatives include the rather unique Scuba Diving Guide Association (Guide-Kai) dedicated to the promotion of Japan’s famous scuba-guides (more on this here).
Furthermore, the steep aging of Japan’s population (Japan has the highest proportion of elderly citizens of any country in the world) has given birth to initiatives such as the Senior Divers Club (SDC) or dive shops with special training programing for elderly divers, such as Midsummer, which aims to keep divers diving up to 100 years of age.

And the Japan National Tourism Association (JNTO) recently created a website dedicated to the promotion of diving in Japan called Japan Diving that we warmly recommend, as one of the most complete on local dive sites in Japan.

We also salute the great work of the Non-Profit Organisation NPO Japan Diving Experience, who is doing a great liaison work, helping non-Japanese speaking divers get in touch with local Japanese operators, and can definitely help you dip your fins in Japanese waters!

A specific legal framework

As a side note, beyond training agency standards, Japan has its own legislation governing the practice of professional underwater activities.

While this legal framework has a strong focus on commercial (industrial) diving activities, it does extend to influence recreational scuba-diving, since diving instructors working in Japan should, in theory, all hold a Professional Diver’s State Licence, the Sensui-shi Menkyo 潜水士免許, to legally operate in Japanese waters.

Diving agencies such as PADI take this into account, as on this info page aimed at future dive pros, clarifying certain aspects related to instructor status and the Japanese Professional Diver’s State licence.

 The Japan Dive Association (JDA) represents licenced professional divers.

This is not so much a “Sport Law” like in France’s legal framework for instance, where all sports instructors are required to hold a State Licence to be allowed to teach and get paid for it, but more of a legislative framework governing all hyperbaric/high-pressure activities in professional settings, where a combination national labour, safety and health laws impose certain practical restrictions.

As an example, Article 15 of Japan’s Ordinance on Safety and Health for Work Under Hyperbaric Conditions (高気圧作業安全衛生規則) legally sets the maximum partial pressure of nitrogen authorised in breathing gas to 400 kPa / 4 bar, which is roughly the ppN2 reached when diving on air at 41m, and rounded down to 40m.
This legal provision is intended to force working divers to stay on the conservative side of gas narcosis management in professional settings.

As such, this legally restricts the maximum depth allowed on any dive using air as a breathing gas to 40 metres.

Textbook for preparing the Sensuishi exam, Japan's professional diver licence
Example of a Sensuishi licence card

Diving style

Shore-diving is very common in Japan, as the country’s long and often heavily developed coastlines offer numerous easy access shore-diving options.

Shore diving is probably the most commonly found type diving on the rocky shores of the main island of Honshū for instance, where some entry points, especially the ones close to or actually on the Pacific-Belt Megalopolis, are often set up for diving activities, with easy-access parking areas, ramps, handrails and entry-ropes, and sometimes showers to rinse the off salt-water, or even hot-springs tubs…
This is one of the positive sides of the concrete landscaping which is said to cover more than 50% of Japanese shores…
Some places offer a more hybrid experience: at the Izu Ocean Park (Shizuoka Pref., Kantō), you register on your arrival and are then free to use the facilities as you wish between 9 am (first entry) and 3 pm (last entry).

One shouldn’t underestimate the possibilities offered by shore diving in Japan.

Local shore dives can offer the standard type of profile, and excellent macro diving, but also, in areas with the right access to deeper water and current exposure, encounters with schools of big fish and pelagic action are not uncommon, especially onthe more remote islands.
There is even the possibility to diver with scalloped hammerhead sharks on an early morning shore dive in the Izu Islands, for instance…

Shore diving, Izu Ocean Park, Izu Peninsula – Image source: expedia.com

Boat diving is also very common, of course, especially on southern islands, mostly done from comfortable, dedicated dive-boats, often equipped with showers, cruising at speed to nearby dive sites, or in some cases, more remote ones, usually near smaller islands that can only be accessed by boat.

In more remote areas, boat diving might also be done from more simple converted fishing vessels.
It’s important to remember that most coastal towns in Japan are still, to this day, fishing communities, and that this can sometimes limit boat access to potentially good diving areas, which are reserved for local fisheries.

In some places boat dives offer advanced current diving, (though perhaps not as wild as what you would encounter in areas like Indonesia, the Maldives or Palau), including good drift dives in areas like Yonaguni, Miyako Kume, Kerama and Amami islands in the Nansei archipelago, or Mikomoto island’s famous hammehead shark dive in Honshū.

Dive boat – Image source: wtp.co.jp

Liveaboard diving in Japan is almost non-existent at the moment (2021), with the exception of a few short, semi-private cruises organised around Okinawan islands, often aimed at select diver populations and groups such as photographers and videographers.

While domestic liveaboard diving is still very uncommon, there seems to be some movement, maybe under the influence of the current Covid-19 restrictions on international travel.
So far, this has been mostly focused the closely connected island chains of the Nansei Archipelago, cruising around various groups of Okinawan islands and also around Kyūshū’s Satsunan Islands.

One operator Stingray Cruises, are organising boat trips and short liveaboard cruises around northern Kyūshū’s Genkai Sea and Saikai area (islands of Okinoshima, Iki islands, and Gotō islands), as well as south Kyūshū’s Satsunan Islands.

Their operation in the Satsunan Islands, Tokara Discovery Cruises, offer 3, 4, 5 and 7 night exploratory cruises around the Tokara islands / Satsunan archipelago area, but for logistical reasons, this is probably still off-the-map for non-Japanese speakers.

More on Japanese liveaboard cruises here, along with some other links.

We’ll see see if domestic liveaboard diving picks up in the future – there are however, practical reasons such as Japanese weather conditions and time schedules which do make organising regular liveaboard cruises a little more complicated than in places like Indonesia or Thailand.

Liveaboard cruise itinerary in the Tokara islands – Image source: tokara-dive.jp/cruise/

Technical diving support is rare.
Unless one is already the member of some sort tech diving community with a local presence, local support for technical diving is generally not available.

One major exception is the Osezaki area (Shizuoka Pref., Kantō region, Honshū island), where an operator is quite supportive towards technical divers, and offers, on advance special booking, a larger range of range of onsite gas-filling options  (nitrox, trimix, oxygen…), along with rental of doubles, Sofnolime for rebreather divers, and aluminium tanks for sidemount configurations.

Guided diving is the norm.
While Japan offers many opportunities for easy-access shore diving, divers actually rarely practice completely autonomous, unguided diving, unlike in the North American context, for instance.
Although there are exceptions, Japan is not generally a place where certified divers can just show up and a dive centre, rent tanks and weights, and go do their thing.

Unguided shore diving is not really encouraged in the country, and most structures i.e. dive clubs and dive centres, will not generally rent tanks, even to certified and qualified advanced divers, if they do not know them, for safety and responsibility.
Some areas might also have specific local rules, stating that all visiting divers must be accompanied by a local dive guide.
There are exceptions of course, such as the previously mentioned Izu Ocean Park (Shizuoka Pref.), where divers have free use of the facilities and rental equipment, organising their own two dives within a set timeframe.

Dive site map – Image source: divingpoint.net

And yet in Japan, most locally organised diving, whether directly from shore or from a boat, will be guided diving, mostly led by a local dive guide following teaching standards and “good practices” given by RSTC organizations.

This is actually often preferable, because good local guides will generally allow you to make the most of your dive through their intimate knowledge of the dive site, and for safety, since conditions can change easily (and let’s not forget the Kuroshio flows at an average of 3 knots in some places off the coast of Japan, which would mean quite a drift for divers caught directly in the main flow…)

And importantly, since this one of the distinctive traits of Japanese diving, local dive guides will frequently be highly knowledgeable when it comes to the local underwater fauna and flora (which is particularly appreciated by photographers), as both dive centres and guides they employ make a point of acting as ambassadors of the local environment they represent.

Japanese guides generally go beyond the traditional roles of “divemaster” and “eagle-eyed local spotter”, and this rarely found elsewhere, except perhaps in certain contexts employing marine biology specialists, or macro-diving specialised areas like Lembeh in Indonesia, for instance.
More on Japanese-style dive guides here.

Snorkeling is common, freediving less so.
Japan also offers some good snorkeling options, but these are mostly concentrated in the southern subtropical areas (Nansei islands, Okinawa region), where shallow coral reefs can be accessed from the beach.
Beware though, some industrial snorkeling operations found in the Okinawa area not really up to standard, and reef fish feeding was unfortuantely still quite widespread until recently (something also found for discover scuba diving / try-dives offered to non-certified divers).

In other parts of the country, snorkeling.skin diving activities may be limited by water temperatures, sea conditions and rocky shorelines – this is not always the case though, and the Nanpō archipelago, for instance, offers good snorkeling spots and guided snorkeling tours, despite more rocky conditions.

For more serious / experienced snorkelers and freedivers, Japanese waters have the potential to offer great experiences, including open water options and the chance to get in the water with large marine mammals, notably dolphins in Mikura-jima and Miyake-jima in the Izu islands, and also, in the cooler season, with migrating whales, especially to the north of Okinawa.

Dolphin swim in Mikura-jima – Image source: ponta-dolphinswim.com

These activities are usually called something like “whale swim” or “dolphin swim“, and while some operators do a great job, you might encounter a great variety in operating standards and practices, notably in terms intrusiveness, awareness and respect of the animal’s well-being across the country.

Some areas like the Ogasawara islands forbid entering the water less than 100 to 150 metres from whales, depending on the species, which limits in water interraction.
This kind of rule might be extended to other areas in the future.

Finally, there is also the possibility to organise a shallow-water freediving experience with ama traditional freedivers in the Kansai region (more on this here).
Breath-hold spearfishing is generally off-limits in Japan, as it requires a permit from local fisheries in most places, pernmit which is not open to non-Japanese nationals, but there might be regional exceptions.

As elsewhere in the world, the freediving community is growing, helped by the fact that Japan has has good results in the competitive freediving scene, including some world record holders in different categories.
Beyond entry-level training, nost of the modern freediving action seems concentrated in the Okinawa region, but this may change in the future…

Dive operators

Japanese divers generally dive through dive centres located near major dive spots, which range from simple dive-shops to all-inclusive diving resorts also offering accommodation and dining options, especially in more remote areas, and everything in between (dive centres able to organise accommodation, etc…).

In most tourism-oriented coastal towns and islands, dive operators will usually have some sort of accomodation option available (hotel, homestay or dorm or a minshuku Japanese style bed and breakfast lodgings), either as cooperation between the dive operator and the hospitality provider, or actually part of the dive business itself.
Because of this, divers will generally have access to some type of package deal including accommodation and meals in a convenient (and often tasty) all-in-one package.

Diving Pension Hoshinosuna, Iriomote, Okinawa Prefecture

Local divers in more urban, landlocked areas also often make use of dive centres located in the city, far from the sea, which offer a hybrid service, somewhere between a diving-club and a travel agent.
These city-based dive centres usually organise regular (weekly or more) diving excursions to different areas of the archipelago.
Some of these urban structures take the form of an associative club, with membership fees, but most are simply commercial structures responsible for organising training sessions and diver certification, as well as selling/renting equipment and taking care of diving logistics for the divers who pay for their services.

These structures will generally offer some sort of transportation service, and can often take care of all the organisational aspects of a dive outing, which is very handy for time-pressed Japanese divers.
On a cultural side note, you’ll see many Japanese operators calling their dive centres XYZ diving service or XYZ marine service, but this seems to be something of a trend and does not represent a specific business category.

Dive center in Ōsaka – Image source: https://www.facebook.com/SukyubadaibingushoppuBonuru/

In all cases, as with many things in Japan, it will be necessary to book in advance.

Most Japanese divers, like the majority of the Japanese population, have much less free-time and vacations than their European counterparts, for example. This does not stop them from going diving very regularly, but also means diving activities are usually very well organized, in an effort to try to waste as little time as possible.

Which also means there is little room for flexibility or improvisation, which is why you should always remember to book in advance, rather than hoping to join a dive trip at the last minute…

It is also better to try to avoid weekends if at all possible, which are often very busy, as well as major holidays, that constitute the peaks of Japanese high season for all leisure activities.
The main holidays to look out for are the Golden Week, a collection of four 4 national holidays within seven days (the core being April 29 to May 5), which, in combination with well-placed weekends, is one of Japan’s three busiest holiday seasons.
The other dates to look out for are the O-bon week (generally August 13 to 16) and New Year’s break (which has less impact on domestic diving since it is in winter) – more on Japanese holidays here.

Diving crowds at Osezaki, Shizuoka Pref. – Image source: fujikaze.cocolog-nifty.com

Payment and pricing


If the structure you’re diving through acts as a booking agent, which is generally the case when diving through a city-based dive centre for instance, you will pay them directly, in advance, and they will handle payments to the on-site dive operator that will be welcoming you.
Remember to check the payment options available beforehand, as credit cards are not accepted everywhere.

Also remember that there is virtually no tipping in Japan – at least not in a standard commercial service setting (some form of tipping does exist, but it is restricted to specific, traditionally defined contexts and highly formalised, of which scuba related activities are definitely not a part of), so there is no need to plan a tip for your dive guide or staff.

If you do want to give something, give little gifts instead, especially snack food and drinks for instance.
As a cultural side note, Japanese divers going diving overseas will often bring Japanese food as gifts for the staff of dive centre where they will be diving – this is highly appreciated by Japanese staff, especially in more remote places where Japanese products are rare!

One place where we worked had a dedicated staff-fridge, always full of delicious Japanese snacks and other temiyage/omiyage, ranging from rice crackers and sweets to bottles of shōchū liquor!

Korean divers often bring cosmetic facial masks as well, along with endless snacks. Maybe you can try to invent your own national gift tradition?

Omiyage – Image source: https://www.jalan.net/news/article/306696/

Diving prices

Diving in Japan is not cheap, in that it is definitely more expensive than what you find in certain locations operating at rock-bottom prices, especially in South-East Asia or the Caribbean for instance.

However, diving is not extraordinarily expensive either, and you’ll find that boat-based fun-diving prices are now, in most cases, roughly on par with many other locations around the world.
And conditions found on boats, along with your typical dive-centre facilities and service, are often superior than what you would find elsewhere, and nitrox, when available, is often free of charge for certified divers.
Diving in Okinawa also tends to be cheaper than elsewhere in Japan.

As a national average, a 2-tank boat will usually be around 130 euro / 160 USD – which is indeed on the high-side, but not incredibly expensive, actually cheaper than places we have worked at in Indonesia’s Komodo, Mexico’s Sea of Cortez or Thailand’s Andaman sea.

That said, some areas, especially in Honshū do charge a lot for shore diving (up to 30 euro/40 USD per tank), but this does include use of dive centre facilities, which again are usually quite superior to what you would find elsewhere, and also the services of a competent dive guide, which, as previously explained, is often mandatory since most dive centres will refuse to simply lend tanks to certified divers they do not know.
As an illustration, Shizuoka’s Izu Ocean Park charges roughly 55 euros / 65 USD for 2 tanks with weights (unguided shore diving), with full use of their facilities between 9am and 3pm. The facilities include  heated changing rooms, 31 shower heads and hot baths in which you can hop in with your dry suits on during the cold winter season (keeping in mind that this is not considered ideal in regards to post-dive decompression / off-gasing…)

Some city-based dive centres and local resorts might offer interesting packages including diving, transportation and sometimes accommodation options.


Dive training courses
(and imported equipment prices, imported brands are often almost 50% more expensive than in Europe or the USA…) are on high side in most cases, so keep this in mind if planning to do dive courses in Japan.

It has also been reported to us that some dive centres sometimes withhold certification, spreading out the training over mandatory, paying training sessions.

We are both diving instructors, and familiar with both club-based dive training (where certifications can take up to one year per level, in a typical French CMAS club setting for example) and the standard 3 to 4 day Open Water-type courses commonly offered in holiday destinations.

While we totally understand and welcome the option to take more time and work on skills with a student (which is one of the great things about regular club training), and also firmly believe you should only certify students truly meeting required skill requirements, we also believe that any extra training required should to stay within the bounds of reason, especially in commercial contexts.
When extra training is required, it should definitely not lead to students paying a lot more than they had be told to actually get certified.

This is hopefully rare, and probably restricted to  Japanese-language environments, but as a general recommendation do ask around, and enquire about the teaching process when planning to do some dive training, in Japan or elsewhere.

Entry level certification, 2 days 1 night program – Image source: blog.mic21.com

Equipment and rental options

Japanese divers often have their own equipment, but many facilities offer do equipment rental options, which is generally well maintained, if a little pricey.

If planning to dive in the cool season or northern waters, however, please note that drysuit rental is not very common, and even if it is possible, it might be difficult to find larger size suits, or even for common builds – this is definitely something to look out for if you plan to dive in Japan in winter.

As a rule, it is best to check what sizes are available, as common clothing and foot sizes in Japan are generally smaller than those commonly found in other countries, which tends to restrict the availability of “large” sizes, both for hire and for sale, especially in dive centres not specialising in a non-Japanese clientele.

Cylinders/ dive tanks are generally made of steel (10L / 12/ 14L steel tanks are the most common, some areas might have 18L as well), but AL80 aluminium tanks (11 litres) so common in tropical locations, are also used in the warmer waters of Okinawa, for example.

If you’ve never dived on steel tanks, the main difference with aluminium tanks is that they become less negatively buoyant at the end of the dive, as you breathe up the air they contain.
They never become positively buoyant at the end of the dive, unlike aluminium tanks. Steel tanks are also heavier (which is why they’re the most common tanks used for diving in cooler waters, where diver more exposure protection), so substract roughly 2 kg from the weight you normally use with aluminium tanks when diving steel.

Please note that outside rare structures offering technical diving service, tank valves in Japan are almost exclusively yoke/INT  – we strongly recommend that you bring a DIN to yoke adapter if you’re diving a DIN first stage like we do, because Japanese dive centres will not necessarily have adapters, or enough for a group of divers with DIN regs…

Independent double-outlet, Y or H valves like those found mostly in continental Europe are also not found in Japan, so remember to set up your octopus on a first stage before travelling if you normally dive with two independent first-stages.

Din > Yoke Adapter

It will be quite difficult to rent twinsets, as commercial support for slightly more “technical” is virtually inexistent outside already established diver communities, with the Osezaki area (Shizuoka Pref.) being the exception to the rule.

Sidemount diving is not that common, but is growing in Japan, in relation with efforts of major RSTC certification agencies to promote side-mount training, but sidemount divers should keep in mind that aluminium tanks are not the norm, meaning that in most places only steel tanks are available…
Remember to check with the dive centre to see if they have no problem with you diving sidemount, and  also confirm their shore/boat logistics.

 Also do check if they have aluminium tanks if required,  and remember to bring spare parts for your sidemount kit.

Even if there is a strong North-American influence is Japanese diving, the country is resolutely metric, and pressure gages are all in bar (and not in PSI).
Weights will also be given in kilograms, rather than pounds.
Likewise, dive briefings will be given in metres, not feet, and temperatures in degrees Celsius/centigrade (for the record, Japanese laws regulating underwater activities give pressure indications in pascal units, kPa, MPa…).
Refer to our metric / imperial cheat-sheet for more info.

Nitrox is often available (check with your dive centre) and commonly free of charge. Maximum operating depths are calculated based on a maximum oxygen partial pressure  of 1.4 bar (and not 1.6 bar like, it is sometimes found some European countries, like France for instance).

When it comes to equipment setup,  Japanese divers are usually quite self-sufficient, at least when it comes to setting up their own gear, especially if it’s their own personal equipment.
Some places might offer to do a basic set up of your equipment, as a service or for practical reasons, especially for boat dives, but this is not the norm, unlike
South-East Asia and other places where it is common for dive staff and/or boat crew to setup customer’s gear for them.

If you would rather set up yourself (and we definitely think you should…), or not have anyone touch your own equipment, make sure to mention this at the dive centre, just in case…

For electronics, Japan uses 100 V / 50/60 Hz voltage (which is the lowest in the world, Europe being 220-240V and the United States 110-120V) and Type A plug sockets, which has two rectangular-pins, that are vertical to each other.
Most devices can handle lower voltages , but battery charging might be slower.

Liability releases and medical certificates

Japanese dive centres will ask you to fill out standardised liability release and risk recognition forms, usually the model provided by the RSTC agency to which the dive centre is affiliated (PADI, SSI, NAUI, SDI…).

Should an accident occur, the exact legal value of these documents is difficult to establish in Japan (the Japanese legal system is complex, and something of a hybrid between civil and common law) but these documents are always required by operators, unlike in European legal contexts where liability release-type documents have little value and their use is now downplayed, or where they might be technically illegal, such as in the French context, where the operator is bound by law to accept responsability.

The dive centre staff should normally do everything they can to ensure your safety, but diving does engage a part of individual responsibility (自己責任, jiko sekinin, which has become a very common concept in Japan), and Japanese dive operators will normally not let you dive without a signature of these documents.

Do note that some dive operators will only have a Japanese version ready to use, and you should, of course, not sign any documents that you cannot read.

When diving with a Japanese dive centre, we recommend that you check in advance that an English version of required forms will be available (all RSTC agencies make multilingual forms available free of charge online, but you must also know how to find them).

While it is always a good idea to do regular medical check-ups and get a doctor’s clearance for diving (especially after entering middle-age and if planning to dive in more stressful conditions such as colder water or current, for instance), it is not a legal requirement in Japan to show recent medical certificate giving you clearance to dive, and Japanese dive centres will generally ask you to fill out with a standard RSTC medical questionnaire instead.

Again, make sure that this document will be available in a language that you can read, and note that if you have to answer “yes” to any of the questions on the medical questionnaire, you will have to see a doctor (general practitioner) and obtain clearance to take part in diving activities.

This is in no way specific to diving in Japan, but you’re not familiar with this kind of medical form and/or think you might have a condition mentioned on it, it could be a good idea to ask the dive centre to see their medical questionnaire in advance, in order anticipate problems, and getting medical clearance, if required, before your trip.

PADI Medical questionaire sample – Image source: pros-blog.padi.com/


Japanese diver centres usually provide some basic insurance coverage for their customers, but this does not extend to emergency hyperbaric recompression treatment.

And this recompression chamber treatement can be very expensive, often in the thousands of dollars per session, keeping in mind that full treatment might require a set of multiple sessions…

This is also in no way specific to diving in Japan, but we strongly advise divers to get specific insurance coverage, clearly covering planned diving activities and emergencies, including medical evacuation and hyperbaric treatments.

Well-known specialised diving insurance provider such as DAN, DiveAssure, Diveassist are a good choice, and some insurance companies like Dive Assure offer packages covering the duration of a single trip.
Another option would be more general insurance policies that also cover recreational diving activities, such as those offered by WorldNomads, SafetyWings or others (but they probably won’t be as efficient in handling diving emergencies as specialist inssurance).

If you are already covered by general travel insurance, make sure to check that it does indeed cover your planning diving activities in Japan or elsewhere, and other key aspects such as hyperbaric recompression treatments and medical evacuation / repatriation from Japan.

Dan Japan has a 24/7 Japanese emergency hotline
+81-3-3812-4999, with an English-speaking operator available from Monday to Friday between 9am and 5pm at +81-45-228-3066 – the operator / medical team can give you advice if you have health concerns after a dive, whether you are a DAN member or not (but only member’s medical expenses are covered)

There are recompression chambers in most major cities and diving areas in Japan, but these can be relatively far from the dive sites, especially in a mountainous country like Japan.
Which means that it is always best to dive conservatively, within the guidelines given by your computer, to maintain slow ascent rates of 10m per minute max, and to remember to stay well hydrated before and after the dive.
It’s also best to go easy on sake, shōchū liquor and other dehydrating beverages when diving the next day.

As a reminder, even though hot-springs are often found next to dive sites (at the Izu Ocean Park, for instance) and as incredibly tempting as it might seem, hopping into the warm waters a hot-spring/onsen straight after a dive is not recommended as it directly affects blood circulation, which could affect bubble formation and possibly interfere with off-gassing…
As with other aspects like sports after diving, jiko-sekinin (self-responsability) or not, it is recommended to wait a few hours before indulging…

Image source: danjapan.gr.jp

Diving certification cards and levels

While Japan does have CMAS-affiliated federations, a branch of the BSAC and a few technical diving oriented organisations (IANTD, etc, see above for more info), the absolute majority of dive centres will be RSTC-affiliated (and mainly PADI for the time being, though this might change in the future, if we consider at the massive growth of SSI diver centres and instructors elsewhere in Asia).

If you are a CMAS-certified diver, and only have a CMAS certification, we strongly advise you to make sure to bring you certification card with you, as it can be difficult to justify your training level without it, since there is no real cross-federation centralised diver database accessible online.

Most dive centre professionals will have no problem understanding your certification level, and the following (rough) equivalence is usually applied:

CMAS * diver  > Open Water diver

CMAS ** diver  > Advanced Open Water diver

CMAS *** diver / CMAS **** > Rescue or Divemaster

Instructor, supervisor, moniteur > OWSI Instructor

Obviously, this somewhat reductive, as the real training situation is much more complex, with very real differences between RSTC and CMAS standards, notably  regarding their approaches to notions of diver autonomy and supervision, the introduction of diver rescue/assistance training and the teaching decompression stops, and also clear differences in depth ranges and ratings.
Nonetheless, this conforms roughly  to ISO standards,  and most structures, in Japan or elsewhere, will apply this type of basic equivalence for the constitution of their groups of divers, and depth “ratings”. 

For more details, you can also refer yourself to our homemade diver level / training agencies equivalence chart below:

While most Japanese dive centres will be RSTC affiliated, keep in mind that RSTC standards are only given for training dives.
As such, RSTC agencies do not specify any actual depth standards for recreational, “fun diving” outside of a training context, and simply recommend divers to stay “within the limits of their training and experience”, and not to dive deeper than 40m.
This maximum depth is in line with Japanese legal requirements defining a maximum partial pressure of nitrogen when diving on air as a breathing gas, as specified by Article 15 of Japan’s Ordinance on Safety and Health for Work Under Hyperbaric Conditions.

This aspect is often misunderstood, even by some dive professionals themselves who wrongly believe RSTC training standards apply actually to “fun dives”.
In the chart above for instance, depth given for RSTC agencies refer to the maximum depths specified in their training standards.

That said, one should keep in mind that, should an accident occur, the dive centre and dive professionals involved will have to be able to justify their decisions and actions, under the angle of duty of care ( which is the legal obligation imposed on an individual to adhere to standards of reasonable care and avoid negligence while performing any acts that could foreseeably harm others).
Standards or not, this is why bringing an inexperienced, Open Water Diver level-trained diver to a depth of 30m+ might raise a few eyebrows, even if it is not a breach of RSTC standards per se.

This is also why, in practice, most RSTC-affiliated dive centres will usually apply the following maximum depths, given for training dives in their agency standards, to actual exploration / “fun” dives :

– 18m max for an Open Water diver,
– 30m max for an Advanced Open Water diver
or more, and
– access to the 30 to 40m depth range given at the discretion of the dive centre/guide
and the diver, depending on their experience, comfort level and/or training.

We hope this clears up the situation, and helps to understand why we all should respect a dive centre and/or dive professional’s sometimes conservative guidelines, and always respect the indications given in the dive briefing and local rules.
Even if this mean diving to a max depth of 30m while avoiding any mandatory decompression stops, when you are trained and experienced in diving to 50m+ dive with deco stops in a different setting.

Diving certification cheat-sheet

Most RSTC-affiliated dive centres will usually apply the following maximum depths, given for training dives in their agency standards, to exploration/”fun” dives:

– 18m max for an Open Water diver,
– 30m max for an Advanced Open Water diver
or more, and
– access to the 30 to 40m depth range given at the discretion of the dive centre/guide
and the diver, depending on their experience, comfort level and/or training.

Metric / imperial cheat-sheet

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