Most people do not associate Tokyo with diving, which is a shame, as there are some remarkable dive sites within 1-3 hours from the Japanese capital by train or car. The wetsuit season in Japan runs from June to September, sometimes early October, and the brave can even attempt drysuit diving year-round.
The Izu Peninsula south of Tokyo offers some of the best diving in Kanto with lots of rocky reefs, shipwrecks, macro diving and even hammerhead sharks! For more sharks, nudibranchs and other marine life, read on.
Looking for the closest Tokyo diving spot? Then your destination is Hayakawa, two stations before the famous Atami seaside resort town, about 90 minutes from Shinagawa and the dive site is only a 10-minute walk from the station. This site is especially good for beginners as it a convenient and easy-access beach dive. The other appeal is its rich macro life: You can find frogfish, nudibranchs, sometimes batfish, octopus, and stingrays in the sand. Check Hayakawa Diving Service (Japanese only).
Next up is of course Atami, a long-standing favorite of Tokyo-based divers, only 2 hours from central Tokyo. Besides diving, it is a hot spring town, and nothing feels better than soaking in an onsen after a dive—especially at the beginning or toward the end of the wetsuit season when the water can get a bit chilly.
Now, the highlight: Atami has a shipwreck! It acts as an artificial reef for soft coral and attracts tons of marine life. There are also other dive sites, most are a 10-minute boat ride from the harbor.
Izu Kaiyo Koen (Izu Ocean Park)
Izu Kaiyo Koen, or Izu Ocean Park (IOP) is another tried and tested dive location close to the capital, about 2 hours and 20 minutes by train from Shinagawa. It offers a plethora of biodiversity under water, including some beauties like angel, damsel and lionfish. If you are lucky, you might see a huge Napoleon wrasse. Also, the macro photographers can look forward to nudies (nudibranchs), frogfish and the like. Check the Izu Ocean Park Diving Center for details.
Osezaki is another dive site on the Izu Peninsula, located 3 hours from Shinagawa station by train. The view of Mount Fuji over the picturesque bay really lets the fact that you are diving in Japan sink in. While it lacks big stuff (e.g. sharks, barracudas and other large-bodied fish), many praise the macro (small things like nudibranchs and shrimps) variety of this site.
A major upside of this dive site is that the bay is sheltered, so it is still divable on a slightly bad weather day, and beginners do not have to worry about currents under water. And according to Dive Zone Tokyo, they started offering night dives in the bay, and from my experience the night brings out (or more precisely up from the deep) some amazing creatures, usually non-scary.
What if I told you that there was a shark-feeding dive, just a 2.5-hour train ride from Tokyo? Banded houndsharks frequently got caught in the set nets of local fishermen, so Tateyama resident Kan Shiota proposed to the fisheries cooperative that he would feed the dogfish to lure them away from the nets—and the plan worked. The sharks now congregate off Ito, where Kan feeds them twice a day.
Seeing around 50 of the slender-bodied hunters is no exception. They are around 1 to 1.50m in length and have a non-aggressive temperament. They politely took mackerel from my gloved hands. The feeding also lures other marine life to the site, so you can look forward to an absolute whirlwind scramble of fish, including moray eels, massive red stingrays, higedai and kobudai (types of wrasse), and Japanese bullhead shark. The shark scramble is a deep dive, so you must be advanced certified or you can take the deep dive specialty on the day with Kan, at Bommie Dive.
Kumomi is most famous for its swim throughs and caverns, a perfect site for those that like interesting underwater topography. The most exciting sea life around is stingrays flurrying over the sand. The town itself is very pretty, and on a clear day its boasts views of a distant Mount Fuji.
The dive is close to a sacred Shinto site on rocks connected by a rope, again, just to emphasize that you are, in fact, doing a very Japanese dive. This is a bit further from Tokyo, about 4 hours by train, so an overnight stay is recommended, but it is well worth it for this adventurous dive. Dive Zone Tokyo organizes trips to Kumomi.
Hammerheads! Hammerheads! Hammerheads!!! Finally, my last recommendation is also a bit further, down at the very southern tip of the Izu Peninsula in the beautiful seaside town of Shimoda. Due to its distance (2.5 hours from Shinagawa) and the long boat ride (usually about an hour) out to the dive site, an overnight stay is recommended. From August to September, juvenile hammerhead sharks school here in large groups. They use the Kuroshio current that flows up from the Philippines along Japan as their highway, and Mikimoto is their pit stop.
This is an advanced dive only, due to conditions like strong currents, large swell and being a pelagic dive. The change of sighting is 50% on average, but it is best to check if they have been sighted with the dive shop via email or on the phone the day before you go. This will greatly enhance your chance of seeing them. The boat ride also makes some people sick, so best to be prepared with some medication if you are prone. There are many dive shops in Shimoda that go to Mikimoto.
Bonus idea: Hachijojima (八丈島)
If you want to make any of the above a day trip, which is the more cheapo option, catch an early train to fit in a morning and afternoon dive. For those who prefer a more leisurely pace, stay overnight and also enjoy some onsen or sento action afterwards, which is available at most of the spots listed.
Another cheapo tip: Some dive spots offer student discounts, like free gear rental (e.g. Bommie Dive in Tateyama), which can knock off a few thousand yen, so make sure to ask!
The wetsuit season runs from June to September, sometimes early October. Most Japanese dive shops have excellent facilities, like proper warm showers where they even provide you with shampoo and shower gel. Many have English-speaking staff and English websites. If you rather leave the organizing to someone else, check Dive Zone Tokyo and Discovery Divers Tokyo for the trips they organize.
Most of the dives from Tokyo are beach dives or a very short boat ride from shore, apart from Mikimoto. That dive location is known to make people seasick, so I recommend you ask for Aneron (アネロン) in a Japanese drugstore. A bit pricey, but it is hands down the best and only motion sickness medicine I take now. Take it at least an hour before leaving on the boat and you are good to go for 12 hours. It says non-drowsy on the package and they mean it, you will be totally fine if your experience is anything like mine.Some people are however unfortunately sensitive to scopolamine. If this is the case for you, it might make you drowsy/nauseous as it contains scopolamine, besides dimenhydrinate, caffeine and some other ingredients.
Finally, the standard tank in Japan is a steel tank, so budget how many weights you add to your belt accordingly (you probably need less kilos than with a lighter aluminum tank). Most of these dive sites don’t service tech divers, as in stuff like side-mounting two tanks, rebreathers or nitrox diving. If that is a must for you, please enquire beforehand or contact Dive Zone Tokyo, who got all the details on techy stuff.
For some more fun in the sun, read our general beach guide for Japan, some of which are dive sites too!