Diving Futo

by Charles T. Whipple

When you chronicle the popular diving spots on the east coast of the Izu Peninsula, you can't ignore Futo — the "Door to Prosperity."

They say diving from boats out of Futo is fine, but most of us make beach entries. And "most of us" can number in the thousands on a busy weekend. Diving at Futo can turn into an exercise in identifying fellow divers, there are so many groups in the water at once. Still, the diving is good. But then, when is diving ever NOT good?

A fishing port turned dive base

Futo Diving Service sits on a bluff overlooking Sagami Bay, near the little fishing harbor that gives the place its name. To the right, the working port; to the left, a path leading down to a rocky beach. Divers have two well-prepared beach entries, complete with concrete ramps and ropes leading down into the water. One drops onto the rocky beach below the bluff; the other lies across the far side of the harbor.

Leave Tokyo early and you can be in the water before lunch. There's room for dozens of vehicles around the operation, but arrive late and parking becomes a puzzle. Futo crowds because it earns the crowd — it sits on the same stretch of east Izu coast as the wider Izu islands and reefs, where the warm Kuroshio Current keeps the marine life generous.

Into the water with the Manatees

Our group of Manatees chose the harbor entry first. The concrete ramp makes a dogleg before sliding down to the water. Sometimes as many as twenty divers are geared up and waiting their turn to follow the rope out into the bay. Buddy assignments set, eight intrepid Manatees shuffled down into the shallows. For thirty meters or so, huge boulders lie in a jumble. Then a sharp drop-off carries you down to a sandy bottom at about fifteen meters.

Whenever you dive in east Izu, visibility is limited right at the entry. But ten meters down, things clear. Cruising along the sand, we could see a good fifteen to twenty meters in every direction.

The Manatee leader clanked her tank to get our attention. Before her, a houbou — a species of searobin — spread its wings yet used its legs to skitter across the sand. We followed it some distance, marveling at the brilliant blue of those wings against the dull brown of its body.

Rockfish, lionfish, and the local cast

Wherever there are rocks, there are rockfish; most in Japan are the spiny variety. And wherever there's a sandy bottom in Izu, the odds of meeting a lionfish are excellent. We spotted two. The great thing about lionfish is their supreme confidence: when a diver approaches, the lionfish simply spreads its fins and invites the intruder to leave.

Time flies, and we started back toward the rock ledge that marks the exit. A tiger moray poked his head from a crevice; another slithered through a field of seaweed. We found the rope and pulled ourselves out, reluctantly ending the first dive of the day.

The water was not quite 21 degrees Celsius, so some of the Manatees shivered in their wetsuits. Relief waited atop the bluff.

The hot-spring boat

Directly in front of Futo Diving Service sits Onsen-maru, an old fishing boat fiberglassed inside and out and filled with steaming water from Futo's hot spring. Two fiberglass tubs of hot water let you peel off the wetsuit, and then you soak away the chill in the boat itself. After lunch, we went again — dive number two, from the rocky beach below the bluff.

Sponge gardens and small wonders

Again the rope leads down from a concrete ramp into large round rocks. Once across the rock bed, the sandy bottom stretches away. We turned left toward the shore to explore rocky outcrops on the sea floor. Sponges, anemones, seaweed, and soft coral cover the rocks, sheltering a myriad of creatures.

Yamazaki, the Manatees' leader, spotted a scorpionfish lying in ambush on a bed of sponge. Turban shells and sand dollars abound; for the first time, I watched one of them feed. Atop one rock, a tiny octopus put on its best camouflage — if you didn't know he was there, you'd never find him. Once more, the sea off the east coast of Izu offered up fantastic vistas for curious divers.

We didn't see sharks or roving tuna or any of the other pelagics. But Futo will, on its day, give up seahorses, frogfish, every kind of nudibranch, swarms of sardines and cardinalfish, skates and flatfish, jawfish and gobies and lizardfish. The sea here is full of nutrients, and the sheer scale of ocean life off east Izu — Futo, the Door to Prosperity — always brings the end of a dive long before you're ready to leave.

Charles Whipple was a writer who lived in Japan for more than 20 years. An avid diver, he contributed diving articles to Australian, New Zealand, Japanese, and American diving magazines, and was always willing to help a visiting diver get acquainted in Japan. Mr. Whipple passed away in 2019. Rest in peace. Copyright of the article and photos on this page belonged to Charles Whipple and now rests with the person who inherited it.

Plan your dive

Futo sits on the east coast of the Izu Peninsula in Ito City, facing Sagami Bay just north of Izu Ocean Park. It works for everyone from first-timers on the gently shelving beach to advanced divers riding the boats out to deeper, current-swept reefs.

• Best season: Year-round. Summer and early autumn bring warm-current visitors riding the Kuroshio; winter trades the crowds for the clearest water and a shot at deep-sea oddities like frogfish.
• Signature sighting: The bigfin reef squid spawning from roughly June to August, often visible even on a beach dive.
• Water temperature: Around the low 20s°C in late summer, dropping toward the low teens°C in winter — a wetsuit serves in the warm months, many divers prefer a drysuit in winter.
• Visibility: Hazy at the entry, then opening to roughly 10–20 meters once you drop below the surge; best in the cool season, though strong wind and surf can knock it down quickly in the bay.
• Level: Beginner-friendly shore entries with concrete ramps and guide ropes; over a dozen boat sites for more experienced divers.
• Getting there: From Tokyo, take the Tokaido Shinkansen to Atami (about 50 minutes), then the JR Ito Line to Ito and the Izu Kyuko Line on to Futo Station, with a short bus or taxi to the coast. Many dive services run their own pickup, so confirm the meeting station when you book.

Plotting a wider Izu trip? Use the Dive Japan maps to place Futo among the peninsula's other sites, or read on to the Izu islands for the offshore version of the same warm-current magic.