OKINAWA

The Okinawa region is Japan’s picture-perfect “(sub-) tropical paradise”, offering Japan’s most tropical, southeast Asian-like diving.
Hard coral reefs, white sand beaches and clear, blue, and generally warm waters that can be dived comfortably all year around, and can even reach up to 30°C+ in the summer months…
Because of the similarities found with “classic” tropical destinations found further south in Asia, and highlights like manta rays and hammerhead sharks, Okinawa is the region most commonly associated with scuba diving and other watersports in Japan.

The Okinawa region has become, along with Honshū’s Izu peninsula, Japan’s main domestic diving hotspot, and is also Japanese diving’s most international destination.

While this can initially be traced back to the area’s specific relations with North America, linked to its specific history and the on-going presence of US army bases, servicemen and their families, the focus has now broadened to general tourism from the world over, and the name Okinawa is increasingly recognised as a tropical/sea-sport/diving destination worldwide.

And, being so physically close to Taiwan’s Taipei and other major cities such as Hong Kong, Seoul or Shanghai, Okinawa is has recently become a popular short-haul dive destination for divers from neighbouring Asian countries.

The Okinawa region counts multiple island group famous for their diving activities, such as the main island of Okinawa, its neighbouring islands (over 80 dive sites), Kume Island and the Kerama island group (Aka, Tokashiki and Zamami) but also, further south Miyako Island and the Yaeyama Islands (which include Ishigaki, Iriomote and Yonaguni Islands, and are Japan’s main manta hotspot).


The islands of the Nansei archipelago form a continuum from the region southernmost islands to the archipelago’s northern islands closer to the coast of south Kyūshū, known as the Satsunan Islands.

The islands were all, until recently, grouped under the name Ryū-Kyū islands, for their physical, cultural and historical links and continuity.
However, in May 2011, an administrative reform decreed that the term Ryū-Kyū would, from then on, be officially reserved to islands attached to Okinawa prefecture with the exception of the Daitō Islands (i.e. primarily the Okinawa, Miyako and Yaeyama Islands).
This means that islands administered by Okinawa Prefecture now roughly form the official Ryū-Kyū Islands (whereas this denomination once covered all the islands of the Nansei archipelago).

From a regional point of view, the island of Kyūshū, along with all the islands administered by both the Kagoshima and Okinawa Prefectures are grouped into a single adminstrative unit, the Kyūshū-Okinawa region, but we separated these two areas for clarity.

See here for more info on the makeup of the Nansei island chain.

MAIN DIVING AREAS MENTIONED

  • Okinawa Islands
    – Okinawa Main Island
    – Kume Island
    – Kerama Islands (Aka, 
      Tokashiki and Zamami)

  • Miyako Island

  • Yaeyama Islands (Ishigaki, Taketomi Iriomote, Yonaguni, Hateruma)

DIVING HIGHLIGHTS AND ICONIC MARINE LIFE

  • Manta rays
  • Hammerhead sharks
  • Other sharks
  • Schooling fish, pelagics and predators
  • Turtles
  • Tropical-style macro critters
  • Whales and other cetaceans
  • Spawning events and aggregations
  • Coral reefs
  • Underwater topography and blue waters
  • The Yonaguni Monument
  • Wreck diving
  • Drift diving
  • Liveaboard cruises
  • Other

MANTA RAYS

The Okinawa region is, by far, the best area to dive with reef manta rays in Japan.

Ishigaki island, in the Yaeyama island group, is the country’s main hotspot for reef manta rays (mobula alfredi), with a healthy population estimated at 300+ individuals circulating around the local islands, and regularly congregating at the Ishigaki’s cleaning stations and feeding points, mostly found in the scenic Kabira Bay area.

The main manta dive site is called “Manta Scramble” as divers and mantas alike scramble from one cleaning station (huge coral bommies) to another, somewhat reminiscent of Komodo’s Karang Makassar, but without the often wild drifting.
This is a shallow dive, the manta action taking place at roughly 10 to 15 metres depth max, with the divers staying low to avoid disturbing the rays which are getting parasites cleaned off by reef dwellers.

While mantas are seen all year round, peak manta season is between June and November, especially the July to September period.
In these months, you will see mantas on the north side of Ishigaki, in Kabira Bay’s famous Manta Scramble area, but also in the Yonara Channel, between Iriomote and Kohama islands, where you sometimes get to see manta mating trains.

From December to April, chances of seeing mantas are higher in the south of Ishigaki. especially near Kuro and Panari and Iriomote islands.
Iriomote in particular, has a number manta cleaning stations scattered on the southern and eastern sides of the island (Kanokawa Bay and Nakanose area), with the main local manta season being January to the early summer months.

While not as common, manta rays are also often spotted (seasonally, usually January to August) around the previously mentioned neighbouring islands, but also near Yonaguni or Miyako islands (especially on the Panata dive site), as well as in the Kerama islands (Shimozone area).

In 2017, reef manta ray cleaning stations were discovered on Kume island (Kume-jima), located roughly 100 km west of Naha, where it now possible to observe mantas all year round.
In Kume, the main cleaning stations are 5 narrow walls lining up from south to north, ranging from 7 to 18 m depth, where the 1st, 2nd and 5th wall sections are considered to offer the biggest chances of spotting manta rays.

Remember to follow the rules and guidelines when observing manta rays, which should be thoroughly explained by the dive operator and guides, and should include never entering cleaning stations or chasing or blocking their path, never touching manta rays, and always leaving them a few meters (3 to 5m) of space to evolve freely in all directions
Keeping the encounter as passive as possible is just better for everyone, and increases the chances of mantas returning to the cleaning station, rather than abandoning them because of divers…
More on this here.

Note
All manta rays are now classified as part of the mobula genus, after a taxonomic reclassification which took place in 2017, (more info on this here) – however Japan’s commonly encountered manta rays are indeed reef manta rays (which are mobulids), and not “mobula rays“, at least in the most commonly accepted sense of the word, as it has sometimes been written.

Japan does have endemic species of mobulas, such as the endangered spinetail devilray, or Mobula japonica, but to make it clear, the rays that have made the Ishigaki area famous are indeed manta rays.

There is also a little confusion/hype surrounding “black mantas” in certain Japanese diver circles.
Yes, melanistic manta rays are sometimes spotted in the Yaeyama or Kume islands’ cleaning stations. They are simply melanistic reef manta rays, not some sort of different species…

Finally, giant “oceanic” manta rays (Mobula birostris) have also been spotted at Yonaguni and Miyako, but also up to Kyūshū’s Satsunan islands (see here), but the vast majority of spottings are reef mantas (Mobula alfredi)

HAMMERHEAD SHARKS

Yonaguni island (Yaeyama Island group) is, along with Honshū’s Mikomoto Islet, Japan’s most famous place to see schools of up to 100 scalloped hammerhead sharks (Sphyrna lewini) mostly from November to June at the Irizaki site, to the west of the island.

The Yonaguni hammerhead dives are advanced current dives in the blue, requiring a negative entry (a quick head-down entry with little to no waiting time on the surface), followed by a drift at 15/20m in blue water (no reference point, hovering neutrally buoyant over a depth of over 70m).
Divers drift along following a team of two guides trying to spot the hammerheads (one guide stays with the group at 15 m whereas the other tries to spot the sharks deeper, at 25m or so).
Once the sharks are spotted, divers may descend to 30m, or for deep-certified/experienced divers to a maximum depth of 40 metres.

Maximum dive time is 30 minutes, for safety and NDLs, and divers are required to catch a current line to return to the boat after the safety stop.

Because of this specific dive profile, a general recommendation is to have at least 50 to 100 dives and good buoyancy control, an Advanced Open Water / CMAS** or more advanced certification.
It is also important to be physically fit and comfortable with current dives and also, very importantly, with no equalisation issues for the rapid, head-down negative entry.

Hammerhead sharks are also often spotted in other areas of Okinawa, including the Yaeyama’s Iriomote, and further up north, around current-swept sites of Kume Island (Tombara area, in the winter months) and the Kerama islands.

OTHER SHARKS

White-tip reef sharks (Triaenodon obesus) and black-tip reef sharks (Carcharhinus melanopterus) are very commonly encountered on the coral reefs of the Okinawa region.

This would need to be investigated, but beyond the regular scalloped hammerhead (Sphyrna lewini) sightings, there is regular talk of tiger sharks (Galeocerdo cuvier) and oceanic black tip sharks (Carcharhinus limbatus) spotted off Iriomote, Yonaguni and other islands in the Yaeyama group, as well in Kume and the Kerama islands.

Whale sharks (Rhincodon typus) have also occasionally been spotted around Kume island (located 100 km west of Okinawa Main Island) and around Yonaguni Island or Iriomote (especially on the San No Ne and Higashi No Ne sites), in the Yaeyama islands group.

SCHOOLING FISH, PELAGICS AND PREDATORS

The Okinawa region offers big schools fish and predatory action, mostly involving trevallies (giant, bluefin, yellowtail, big-eye trevallies) tunas (dogtooth tuna) barracudas and rainbow runners.
These predatory fish are commonly found across all Nansei islands, but particularly in the Kerama islands (Sakurabu, Shimozone) or Kume, where current conditions bring large pelagic predators to the reefs.
The region also has healthy populations of reef sharks (white tips and black tips), and other usual reef inhabitants such as cuttlefish, eels, etc.

Aguni Island, roughly 60 km west of Okinawa Main Island, is famous for its large ball of bigeye trevally (Caranx sexfasciatus).
Along with trevallies and tunas, “tornados” of barracudas are often spotted around Yonaguni island (Yaeyama Islands), along with the odd sail-fish!

Iriomote’s current-swept sites of Higashi No Ne or Sakiyama Oki No Ne, Tokakin No Ne are all famous for their schooling and pelagic action, and the San No Ne site can see aggregations of over 1,000 bluefin trevallies if current conditions are right.

Kume island’s Tombara and Imazuni areas are also famous for current swept schooling action with dogtooth tunas, bigeye trevallies, manta rays, spotted eagle rays, and even the odd whale shark.

Schools of cownose rays (Rhinoptera bonasus) and other mobulids have also been spotted in the Kerama islands (Aka-jima area) in the spring months.

TURTLES

“Sea” turtles are often spotted on pretty much all islands of the Okinawa region, but are particularly frequent on Miyako and the Yaeyama islands (Iriomote, Kuro, Ishigaki…)
They are also frequently seen in the Kerama islands, on sites such as Gishippu, which is home to healthy populations of hawksbill and green turtles (Eretmochelys imbricata and Chelonia mydas)
Near Okinawa Main Island, Kudaka Island (south east of Naha) and the Chibishi Islands (west of Naha) are famous for their green turtle populations, as well as seasonal nesting of loggerhead turtles (Caretta caretta).

Kume island, 100 km west of Okinawa Main Island, has a site called Turtle Paradise (“Kame Paradise”) where it is sometimes possible to see 50 or more turtles resting on the reef.

TROPICAL-STYLE MACRO CRITTERS

The Okinawa region also offers a great variety of warm water macro critters and rare colourful fish, similar to those found further south in South-East Asia, especially in the Yaeyama or Kerama Islands.

Interesting critters found include:

Nudibranchs (especially Okinawa Main island’s mucky sites like Kinwan Bay)
Frogfish/anglerfish
Bobtail squids or the flamboyant cuttlefish,
Mandarin fish or elegant firefish,
Electric clams,
Leaf scorpionfish and other rare scorpionfish
Crabs and shrimps (including the photogenic emperor shrimp)
Ribbon eels and Jawfish
Pigmy seahorses (Hippocampus bargibanti,. h. colemani and h. pontohi)
Pipehorses, various pipefish and ghost pipefish

WHALES AND OTHER CETACEANS

Migratory whale watching is big in the Okinawa region, in the winter months, especially to the north of Okinawa’s main island.

The Kerama islands are one of Japan’s main humpback whale watching hotspot, especially between December and April.

Humpback whales (Megaptera novaeangliae), sperm whales (Physeter macrocephalus) and pilot whales (Globicephala) and false killer-whales (Pseudorca crassidens) are also spotted in the Yaeyama islands during their migration north in the winter months.

Humpback whales are also sometimes spotted near Kume Island, roughly 100km west of Okinawa Main Island, especially in the Tombara area in the winter months.

More on whale watching in Okinawa here.

SPAWNING EVENTS AND AGGREGATIONS

Broadclub cuttlefish (Sepia latimanus) are commonly spotted on all reefs of the Okinawa region, but they’re especially common between winter and spring around Ishigaki island, culminating in early March, when impressive mating then spawning events take place on the west coast of the island.

Iriomote island is famous for its coral spawning events, that very lucky divers can observe on night dives from May to September, roughly a few day after the full moon.

CORAL REEFS

The Okinawa region is famous for its healthy hard coral reefs full of life – especially in the Kerama (Zamami’s Chishi dive site for instance) or the Yaeyama islands.
Miyako island is also famous for its staghorn and table coral (over 100 reefs) and gorgonian seafans.
The islands of the central Okinawa area also have beautiful soft coral colonies and gorgonians, such as the Unanzaki area in the Kerama islands, or Sunabe Seawall on Okinawa Main Island, or the Ohama Sango site on the Chibishi Islands, just a 10 minute boat ride away from the main island, famous for its colonies of Porites lutea stony coral, where 10 metre wide bommies reach a height of up to 8 metres.

UNDERWATER TOPOGRAPHY AND BLUE WATERS

The islands of the Okinawa region are primarily made of coral limestone or volcanic rock, and thus often present complex and interesting underwater topographical features.

Out of these, Miyako’s group of 6 islands is very famous for its coral limestone-based underwater environment, where rain and seawater erosion gave birth to a multitude of caverns and caves (especially in Irabu and Shimoji islands), tunnels and swim-throughs, canyons, boulders and arches, which make for fun exploration dives.

Miyako’s topographical highlights also the island’s famous Blue Cave, the W-Arch, the two-chambered Maō No Kyūden, the Cross Hole, where light shines through cracks in the rocks.
Another famous site is Gakeshita, where you can surface inside a large volcanic boulder, only to be surrounded by a misty vapour, formed by rising and falling water levels in this highly humid, closed-off environment.
Equally famous is Tori-ike on Shimoji island. The site consists of two small ponds connected underwater, where you can experience the mysterious effects of chemoclines and thermoclines when swimming from one to the other.

Okinawa Main Island also has a famous Blue Cave at Cape Maeda, where incoming sunrays give the cave a distinct blue hue similar to Capri’s Blue Grotto in Italy, and is also famous for the Manza Dreamhole, which is a narrow vertical tunnel which you can follow towards the seabed, before turning 90 degrees and leading to the outside reef.

Ishigaki’s southern tip also hosts Japan’s largest coral lagoon, the “Sekisei Shōko” with coral bommies, sandy bottoms and caves (picture here)

The Okinawa region is also generally famous for offering excellent seasonal visibility and clear blue waters, especially the Kerama Islands (Aka, Tokashiki and Zamami), famous for their Kerama Blue seas, or in the Yaeyama islands, especially Hateruma Island and its renowned year-round Hateruma Blue.

THE YONAGUNI MONUMENT

Yonaguni island’s “Monument” or Yonaguni Submarine Topography, is made up of massive monolithic rock formations of very fine sandstones and mudstones, that look somewhat man-made and have been the subject of passionate pseudo-archaeological speculation since their discovery in 1986 by Mr. Aratake, who is also the founder of Yonaguni’s Sou-Wes dive centre.
Whatever the truth behind the rock formations might be, they surely make for a unique, atmospheric exploratory dive, which might trigger your imagination, especially after with a little nitrogen build-up!

The Monument is found in relatively shallow waters, the bottom of the main structure sitting at about 25 metres, while the top is roughly at 5 metres.
However the site is an advanced dive site, as it is generally swept by strong currents,

Beyond the monument (and schooling hammerheads!), Yonaguni island is also famous for its topography, with plenty of caverns (including the Cavern of Light / Hikari no Kyūden site) and many swim-throughs for divers to play around with, along with excellent seasonal visibility.

WRECK DIVING

The Okinawa region was the stage of fierce battles at the end of WWII, and there are many wrecks lying in its waters.
These wrecks are not all easily accessible, and some require special equipment and adequate training, or a permit, so do your research in advance.

One of the most famous of these wrecks is the USS Emmons, resting close to coast of Okinawa’s Ko-uri island (also famous for its heart-shaped rocks…), roughly between 36 and 45 metres below the surface.
This 106 m long vessel was hit by five kamikaze (tokkōtai) suicide attack planes, and was deliberately sunk by its United Statian crew, after heavy damage and loss of life.

Because of its depth, the USS Emmons wreck is an advanced dive, which ideally requires special training and experience (more than 50 deep dives) to be dived to the max recreational depth of 40m, and extra equipment to be explored efficiently beyond.
The USS Emmons wreck is also commemoratively dived by Japanese and American divers on the yearly anniversary of its sinking.

DRIFT DIVING

The Okinawa region offers solid drift dives options, especially at current swept site like Yonaguni, Miyako and Kume islands, or in some sites of the Kerama islands, where you’ll have chances of seeing bigger pelagics, sharks, and predatory action.

LIVEABOARD CRUISES

Liveaboard diving is not common in Japan, however there is some movement around the Nansei Islands, with some cruises offered (maybe under the influence of the current Covid-19 restrictions on international travel) in the area.
Some cruises were recently organised around closely connected island groups in Okinawa (Kerama and Okinawa Main island, Yaeyama Islands) and also around Kyūshū’s Satsunan Islands.
These are semi-private cruises organised around Okinawan islands, aimed at select photographers and videographers and more are, for logistical reasons, still quite off-the-map for non-Japanese speakers, but this might change in the near future. Stay tuned!

OTHER

An underwater mail box was setup in April 2016 on Okinawa main island’s 5 Sunabe No.1 dive site, in the Chatan area.
As elswhere, divers can buy water-resistant postcards, write messages on them with an oil-based paint marker and post them in a postbox situated underwater.
The letters are collected from the postbox every few days, taken to the local post office for processing…

Click here for more precise, detailed and practical information on diving in the Okinawa region.

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