Subtropical Japan's diving hub pairs easy shore diving on Okinawa's main island — including the famous Blue Cave at Cape Maeda and the 40–46 m USS Emmons wreck — with the Kerama Islands, a national park since 2014 famed for crystal-clear 'Kerama blue' water, 248 coral species, sea turtles, and humpback whales that breed there each winter.
Conditions, highlights, and the resident marine life.
Water and air temperature across the year.
Okinawa, Japan's southernmost prefecture in the Kuroshio-warmed East China Sea, combines two distinct diving worlds: the main island's accessible coast — the hugely popular Blue Cave at Cape Maeda, reef holes and tunnels along the Onna/Manza coast, and the USS Emmons, a US destroyer-minesweeper struck by five kamikaze aircraft on 6 April 1945 that now lies at 42–46 m off Kouri Island — and the Kerama Islands, a cluster of more than 30 islands 20–40 km west of Naha designated Keramashoto National Park on 5 March 2014. The Keramas' famously clear 'Kerama blue' water (commonly 20–40 m visibility, up to 50 m on the best days) covers reefs with 248 recorded species of reef-building corals, served by day boats from Naha and the island villages of Zamami, Aka, and Tokashiki across roughly 100 dive sites, most of them calm enough for beginners. Water temperatures range from about 21°C in late winter to 29°C in high summer; humpback whales breed and calve in Kerama waters from late December to early April (watched from boats — in-water encounters are not standard practice), the rainy season runs May–June, and typhoons can disrupt boat schedules between July and October. A strong domestic dive industry operates year-round, with English-speaking operators available on the main island and in the Keramas.
What makes this dive worth the trip.
28 species you’re likely to encounter on a dive here.
7 signature sites at this destination.
A tiny islet between Nakajima and Gishippu islands northeast of Tokashiki, ringed by some of the healthiest hard coral in the Keramas. The north side holds a shallow coral lagoon that drops onto one of Okinawa's most impressive vertical walls, while the south side offers gentler sloping coral mounds; depths run to about 40 m. Turtles and reef sharks are regular, and lucky divers occasionally meet a manta off the wall.
Crevasses, arches, and small caves cut into the rocky point directly below the Aharen lighthouse at Tokashiki's southwestern tip, with most diving between 5 and 20 m. The site is best known as a spring spawning ground for broadclub cuttlefish, which gather over the coral heads to court and lay eggs; the swim-throughs and skylit cracks make it equally popular for topography.
A manta cleaning station off the uninhabited islet of Ijakaja between Zamami and Aka islands, inside the Ramsar-listed core of the Kerama reef. Reef mantas visit the cleaning bommies most often between May and October, and sea-turtle encounters are reliable year-round on the surrounding coral slopes, which run down to about 30 m. Calm conditions on most days make it one of the few manta sites genuinely open to newer divers.
Japan's most famous easy dive: a limestone sea cave on the north face of Cape Maeda on Okinawa's Onna coast, entered from a shore stairway of 90+ steps or by boat. Sunlight filtering through the entrance turns the water inside an electric blue, and the shallow reef outside is so thick with fish that operators compare it to an aquarium. The cave itself is only 2–7 m deep, with reef and wall diving to around 12 m on the standard circuit, making it a staple first dive — and extremely crowded with snorkelers and try-divers in summer.
A 106 m US Navy destroyer-minesweeper lying about one nautical mile off the northern end of Kouri Island, with the bow at roughly 42 m and the stern at 46 m. Hit by five kamikaze aircraft on 6 April 1945 and scuttled the next day, the wreck still carries depth charges in their racks and guns with rounds loaded; the torn aft section lies scattered across the seafloor. Depth keeps no-decompression time under about 10 minutes, so the wreck is typically explored over two dives from fixed descent lines. A war grave for 60 sailors — annual US–Japanese memorial dives are held here — it demands respect: no penetration, take nothing.
Often cited as the best all-round reef in the Kerama Islands, off the white-sand Nishibama Beach on Aka's northeast coast. Vibrant hard-coral gardens slope from the shallows to about 26 m over white sand, home to clouds of green chromis and pink basslets (sea goldies), cardinalfish, red-spotted groupers, and colonies of garden eels on the sand flats. Suitable for beginners when the current is slack, with classic 'Kerama blue' visibility.
An L-shaped tunnel through the reef edge just off Cape Manzamo on Okinawa's Onna coast: divers drop vertically through a narrow chimney that opens at 6 m, descend inside the rock, and exit through a fish-curtained mouth at 25–28 m on the outer wall. Big lobsters, stonefish, and scorpionfish shelter inside, with garden eels on the sand beyond the exit. Boat access only, and the overhead environment plus depth make it a dive for experienced divers — most shops ask for Advanced Open Water and around 30 logged dives.
Local dive centers, resorts, and hotels.
Verified dive centers, resorts, and hotels around Okinawa (Kerama) will list here — pricing, photos, and direct contact.
