Diving Day Trips Around Tokyo
Text images by Aaron Wong, unless where specified
Professional underwater photographer Aaron Wong tests the waters around Tokyo and reports his findings.
Mention Tokyo and it is safe to say scuba diving comes low on the usual list of to-dos in Japan. But that should all change and for good reason. After all, Japan is an island nation and Tokyo, being on the east, is flanked by the Boso and Izu Peninsulas. These Pacific-facing peninsulas are blessed with good topography and upwelling currents that bring along an amazing multitude of marine life, from schooling hammerheads to rare critters found nowhere else.
The journey there was very straightforward. I flew in to Tokyo with JAL, which offers free baggage allowance for dive gear. This is a great plus, especially for underwater photographers.
MIKOMOTO
HIGHLIGHT: WALLS OF HAMMERHEADS
Known for its beautiful coastlines, the Izu Peninsula has long been a hot sea sports destination for many in Tokyo who want to escape the buzz of the city. Hidden in its southern tip is the well-kept secret of Shizuoka Mikomoto.
It is possible to get close to the hammerheads in relatively shallow waters between 15 and 25 metres
ALL IN THE NAME
They have basic ryokan (traditional Japanese rooms) above the dive shop, but you can also book other hotels near the Izukyu Shimoda station, where they will be happy to pick you up every morning. As the name clearly suggests, Mikomoto Hammers is all about the large schools of hammerhead sharks that follow the warm Kuroshio Current right up to Mikomoto Island with its iconic lighthouse.
The island is a short 20-minute boat ride from the harbour, which is when everyone starts gearing up. The descent is done quickly so you do not miss the spot, and I was almost immediately greeted with the largest school of scalloped hammerheads I have seen – 200-plus strong, just casually cruising along.
WELL WORTH THE DIVE
They are rather accustomed to divers, so getting close to them is possible. Being in the right place at the right time certainly helps. There can be a fair bit of finning to fight the current, which was something I learned the hard way with my shorter fins. But when you get it right, the experience of diving with the wall of hammerhead sharks is well worth it!
BEST TIME TO DIVE
Diving with these hammerhead sharks is possible all year round, as the winding of the warm Kuroshio Current has been documented since 2017. But the best months are between June to October, where sea conditions are calmer, and visibility can reach 30 metres. Depending on the month, water temperatures invariably affects the behaviour of the sharks and how you dive them. In June to July, there are fewer warm currents, causing the sharks to gather in tighter schools nearer to Mikomoto Island.
I got there in August where the water was a comfortable 25°C and because of that, they were more spread out, with the school stretching out into the blue. I had the hammerheads on all my four dives. While it is known that the collision of warm and cold currents brings an abundance of marine life, it can sometimes wreak havoc for divers with strong currents and thermoclines. So I would suggest at least a 5mm wetsuit and long fins, but if you do not have them, you can always rent from the guys at Mikomoto Hammers.
OSEZAKI
HIGHLIGHT: CRITTERS AND VIEW OF MOUNT FUJI
Located on the western edge of Shizuoka Izu’s Peninsula, Osezaki is a kilometre-long outcrop of land that extends into the Suruga Bay, overseesing Mount Fuji to the northwest.
GUIDED SHORE DIVES
You can dive the outer reef, which faces Mount Fuji, or the inner side within the bay, which is where all the macro critters are. On weekends, you can also dive the tip of the beautiful cape (sentan).
On clear days, the majestic view of Mount Fuji greets you as you surface from your dive. Image by Kenji Ichimura
All these sites are shore dives so be prepared to do a little walking. The dive centre offers trolleys that you can put all your gear in and cart where you want. All dives in Osezaki have to be guided dives, so you will always have someone show you around. Osekan Marine Service has English-speaking guides, a huge advantage for overseas divers. I started with the outer reef, with a beautiful pebble shoreline dropping fairly quickly to 50 metres. The reef is covered with beautiful soft corals, schools of cherry anthias, and dragon moray eels probing amongst the rocks.
The water can get cold at depth even in the summer, so a minimum of 5mm is a must, but surfacing on a clear day with Mount Fuji in the background is a great experience in itself.
THE MAJOR ATTRACTION
The real draw for me were the critters within the inner bay. It is a black sand site very similar to the Lembeh Straits and Anilao. Rhinopias, ghostpipefish and, if your stars are aligned, even the endemic Hippocampus japapigu pygmy seahorse, can be seen within this sheltered bay. The entire site is well-mapped out with plenty of underwater ropes and structures for you to easily find your way around.
With keen eyes, one can spot the Hippocampus Japapigu pygmy seahorse endemic to Japan within the Osezaki Bay. Image by Kenji Ichimura
You can also do blackwater dives on Wednesdays and weekends right next to Suruga Bay, the deepest bay in Japan at over 2,400 meters. Like all other sites in Japan, it changes with the seasons, so if dry suits are your thing, a whole new host of critters await.
TATEYAMA CHIBA
HIGHLIGHT: SHARK SCRAMBLE
Ito Tateyama is at the southern tip of Chiba Prefecture, in the southeast of Tokyo, and the home of a very unique shark diving experience.
Hundreds of houndsharks cruise the reef before and after the feeding sessions
THE MAN WHO MADE IT HAPPEN
Fifteen years ago, Mr Kan Shiota was looking for a spot in the Boso Peninsula to start a dive shop, when he was asked by the local fishing association to help with a long-standing problem they had with the banded houndsharks in the area. They were often caught in the fishing nets, damaging them and the fishes within. They wanted Kan to redirect the shark colony somewhere else. Usually shy of divers, the sharks finally trusted Kan and started moving away from the nets only after over five years of persistent baiting.
With Mr Kan Shiota himself, the man who protected and cared for these houndsharks for over 15 years
CREATING A DOUBLE WIN
Today, even after many of these fisheries ceased operations during the COVID pandemic, Mr Kan continues to help other fishing associations around the area by collecting the bycatch, using them to keep the sharks in one area, and prevent the sharks from becoming bycatch themselves. The shark population inevitably grew within this specific reef, and this is now a truly unique diving experience. In addition, the revenue generated helped the local fishing association and boosted the area’s economy.
Needless to say, this story and the possibility of diving with hundreds of friendly banded houndsharks was just too good to pass up.
FUELLED BY PASSION
I was greeted by Mr Kan himself, and he and his crew were very helpful in settling me in. I could still see the passion in his eyes and the fact that he could speak English was a plus. The dive shop and washing area were big and spacious, making the gearing up a breeze because, like everywhere else in Japan, divers are expected to set up their own equipment.
SCRAMBLE BEFORE THE SCRAMBLE
The boat ride to the famous site was a short five-minute ride, so you have to be ready to dive. The currents can be strong, but there are mooring lines that will guide you down. When you finally get to where the action is, the water is strangely calm.
THE SHOW
Schools of large amberjacks and rays patrolled the reef while over 50 stars of the show hovered around the sandy bottom. Once the dinner bell was rung, a hundred more showed up out of nowhere. These sharks and rays were truly friendly and would rub against you from all sides. It was indeed a scramble in the fullest sense of the word and certainly an exhilarating experience. The water was a little cold at 21°C, but the adrenaline will keep you going. That said, a 5mm wetsuit and hood is recommended. I would also suggest wearing gloves, because friendly but frenzied sharks with little teeth can easily turn into buzzsaws.
The dives are relatively short, as the site flattens at around 20 metres, so you have to keep a good eye on your no-decompression limit. Spending the day doing two 25-minute dives with these sharks was just perfect.
The eight days I spent diving near Tokyo has shown me a side of this island nation I never thought I would see. While the language and culture barrier might deter some of us, the beauty underwater should surely lure us into uncovering her secrets. While many of us have our sights on more established dive destinations around Southeast Asia, it is perhaps time we take a good look at this gem so many of us have overlooked. After all, she is indeed an island surrounded by sea.
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