December 2015: Miyagawa Bay, Kanagawa, JAPAN

Saturday December 5th, 2015

The waves gently wash against the side of the boat as we arrive at our dive site. The water seems clearer than I was expecting, with small shoals of tiny fish circling near the surface.  As I descend they’re barely visible through the thick blur of thermocline, but looking more closely they’re picked out sharp against the sun piercing through the water.  There aren’t all that many of them but the small swirling shoal is a welcome and unexpected sight here at Miyagawa Bay.

With its clusters of rocky structures, outcrops and boulders, Miyagawa Bay has been worn down by the action of the waves. It’s a convenient little diving area close to Tokyo, with a series of rock formations waiting to be explored, waters full of soft coral, various species that cover the rocky walls, anemones that fight for space and dives that are packed with colour.  The macro life here is particularly excellent.

We began with the dive site Kasagone, dropping into the water beneath a distinctive cliff-face rock formation.  I descended past a huge rock and a small chamber that opened out into a corridor with its walls almost devoid of life. My light cast eerie shadows along the walls and my splashing about caused a resident eel to look up and hide at the very back of its den.  Swimming past the rock and down to about 15m, I swam straight down a steep rocky wall and, following my guide, ducked beneath some boulders in search of any macro life I could find.  Half-lined cardinal fish flitted about in the blue close by as I followed the boulders around, eventually reaching an area at 16-19m that resembled nothing more than a sandy carpet, with more boulders and rocks dotted here and there. Settling in, I noticed that the site was covered with impressive growths of sponges, soft corals, gobies, nudibranchs and macrolife aplenty.  A black sided pipefish hovered in a tiny crack in one rock, while seductive seahorses, nudibranchs and determined not-to-shift frogfish immediately tempted away the close-up photographers in our group.  I was blown away by the seahorse and able to get very close for a few photos. Hanging out by the rock and taking in its colour and markings as it swayed to and fro in the mild current was simply stunning.

Our next site, Tobine, proved to be just as exciting.  Starting at 10m down a series of rocks, we descended slowly towards a swim-through tunnel carved out of rock and covered with substantial growth including soft coral and sponges.  Moray eels and pipefish hid between the rocks, some with their cleaner shrimp companions, but we’d come here to find harlequin shrimp.  Our guide shone a light into a small cave-like opening and sure enough, there he was, white and blue in the torchlight, watching us sternly as we took turns moving closer for a few photos. There were gorgonians, whip coral and fans everywhere at Tobine, while nudibranchs combed the rocks, a range of them munching on seafans and other growth along the rocks, and the odd two or three sat in gaudy splendour.  This is also a site where you can spend frustrating minutes attempting to find and photograph the small and shy wire coral goby as it sways here and there in the swell. There is a lightly encrusted layer of marine life over the rest of the rocks, with the occasional fish grazing on the growth and cleaning it up.  Before ascending, we popped out on a sandy plateau at the 20m mark and looked up at the quirky, distinctive rocky topographies.  Visibility was around 10-15m, enough to make out the impressive structures rising up into the blue. Nudibranchs, soft coral and even a few sea goldies distracted me as I made my way to the surface.

Visibility here is rarely crystal clear but it can vary tremendously.   Above all, however, prepare yourself to be blown away by the macrolife that has colonised the area. You’ll see a huge amount of nudibranchs, shrimps and tiny critters — surprising for a dive site so close to Tokyo. Everything is in profusion, abundance or even superabundance.  If you want leisurely dives at no more than 20m and plenty of photo opportunities, Miyagawa Bay won’t disappoint.

Practical Information

  • We took an early morning train (Keikyu Line) from Tokyo’s Shinagawa station at around 7:34AM and arrived at Misakiguchi station around 08:50AM.  A single ticket from Shinagawa costs 926yen and the journey takes around an hour and 15mins.
  • We were met at the station by staff from Nana Diving Shop ( and taken to Miura Dive Center, a relatively old building at a harbour. The first floor is a communal area (wetsuits allowed), while the second floor consists of a series of tatami rooms where customers can get changed and leave clothes.  The building is quite old and run down but very spacious.
  • Next door to the building are a few showers (ask the staff for shampoo and body soap, otherwise bring your own including a towel) and free tea is available from the dive staff.
  • After changing into your wetsuit or drysuit upstairs, come down to the communal room and leave a small bag including towel, water, sunscreen and anything else you might need in between your dives.
  • The boat is small with room for about 20 divers to sit next to each other.  There is no shade.  Customers set up outside the shop next to the harbour and put their gear on once they are on the boat.
  • The dive sites are no more than 5 minutes away from the harbour.  On clear days you can see Mt Fuji from the boat as well!
  • All entries are backward rolls, and the descent is along a fixed rope.  Ascent is up a ladder.
  • After a briefing at around 09:50AM, the boat leaves for the first dive around 10:00AM.  It then leaves for the second dive around 11:45AM – 12:00PM and returns at 1:00PM in time for customers to get changed, shower and wash gear.
  • Around 2:00PM the staff drive you to one of the local seafood restaurants for lunch. Raw tuna, rice, miso soup and beer are all available. Lunch is also a chance to fill in logbooks and go over the day’s dives.
  • After returning to the dive centre to put gear away, the staff drive customers back to Misakiguchi station around 3:00PM.
  • Nana Diving Center is based in Hayama, slightly north of Miyagawa Bay.  Beach and boat dives are available in the Hayama area, while boat dives only are available at Zushi and Miyagawa Bay.
  • Two boat dives at Miyagawa Bay cost 13,000yen including tanks, guide and weights.

December’s dives

Dive 1: Kasagone: dive number: 215, depth: 19.5m, dive time: 48mins, entry time: 10:19, exit time: 11:07, water temp: 19C, water visibility: 15m, Start pressure: 190 bar, end pressure: 40 bar, used a 10L steel tank, 5mm wetsuit, 3mm hood/vest and 3kg weight (backplate only).  Saw neoclinus toshimaenis, Japanese seahorse, lion fish, banded coral shrimp, half-lined cardinal, banded gobies, black sided pipefish hovering in rock, chromodoris orientalis (white nudibranch), hypselodoris festiva (blue nudibranch), jorunna parva (nudibranch), splitlevel hogfish and frogfish.

Dive 2: Tobine: dive number 216: depth: 18.1m, dive time: 46mins, entry time: 12:19, exit time: 13:06, water temp: 17C, water visibility: 15m, start pressure: 200 bar, end pressure: 50 bar, used a 10L steel tank, 5mm wetsuit, 3mm hood/vest and 3kg weight (backplate only).  Saw harlequin shrimp, frogfish, glossodoris rubroannulata (nudibranch), glass fish, parrotfish, damselfish, threespot dascyllus, goniobranchus tinctorius, yellow chromis and sea goldies.


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