Ryusendo Cave
licensed photographあおもりくま / Public domain

North Iwate · IwaizumiNo.577★★★Open in map →

Ryusendo Cave

natureThe classic — done right

A limestone cave in the mountains of northern Iwate, known for underground lakes of an intense, unusually clear blue. The walking route passes a bat hollow and a lit stalactite hall before turning back at the deepest lake open to visitors.

  1. FromMorioka Station
  2. ~2 h 15 minJR Bus, direct from Morioka
  3. Get off atRyusendo-mae (JR Bus Tohoku, Hayasaka-Kogen Line)
  4. On foot
  5. Ryusendo Cave
Directions ↗

Where it is

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What to look for — in walking order

First Lake lookoutYasu / CC BY-SA 3.0
  1. Hyakken Corridora long straight passage following a fault line, where the walking route begins
  2. The bat hollowa side chamber used as a roost by the bats that live in the cave
  3. Gekkyuden halla wide stalactite chamber named for a palace on the moon, now under LED light
  4. The Third Underground Lake98 metres deep, the far end of the visitor route, seen over a railing
  5. First Lake lookouta platform above the first lake, looking down through stalactites to the water

How to actually get there

  1. Morioka Station East Exit → Ryusendo-mae (JR Bus Tohoku, Hayasaka-Kogen Line).
  2. Ryusendo-mae → the ticket gate, on foot across the park beside the river.
  3. Walk in past the bat hollow and Gekkyuden to the Third Underground Lake, then climb back over Mihara Pass to the exit.
  4. Return from the same stop on the last run to Morioka, or stay the night in Iwaizumi.
JR Bus Tohoku, Hayasaka-Kogen Line from Morioka
Morioka Station East Exit to Ryusendo-mae, one seat the whole way, about two hours and a quarter. The operator lists the one-way fare at 2,710 yen and runs four departures a day, the first leaving at 9:10. There is no toilet on board, but the bus takes a short break at the Mitagai Bunko roadside station.
Last bus to Morioka leaves at 16:00
Buses leave Ryusendo-mae for Morioka Station East Exit at 6:00, 7:00, 8:00, 14:00 and 16:00, and the 16:00 gets in just after 18:00. Nothing runs later, so an arrival on the late-morning bus makes the 16:00 the only realistic way back the same day.
Directions from my location (Google Maps) ↗

About the place

Ryusendo opens into the limestone under the hills at the edge of Iwaizumi, a small town in the mountains of northern Iwate. Surveyors have mapped 4,088 metres of passage, and the system is thought to run beyond 5,000 metres, so the walking route covers only a fraction of it. What people come for is the water. Rain that has filtered down through the limestone gathers in underground lakes, and the blue reads as colour rather than as reflection. The clarity is rated among the highest anywhere, and the cave is counted as one of Japan's three great limestone caves.

How to enjoy it

The timetable decides the shape of the day. The first bus out of Morioka reaches Ryusendo-mae late in the morning, which leaves the cave, the park around it and the science museum comfortably inside one afternoon before the return run. Wear shoes with grip: the walkway is wet the whole way and the return climbs.

Background & history

Ryusendo was known in Iwaizumi long before anyone measured it. In the last century a party of local men worked their way into the dark, found the hollow where the bats roost, and the stretch nearest the entrance was opened to visitors within days. Diving surveys in 1968 went down into the third underground lake and filmed it from below. The cave and the bats living in it carry a single designation as a national natural monument, and the survey work has never been finished.

Before you go

Cash
At the time of checking, admission was 1,100 yen for high-school age and above and 550 yen for elementary and junior-high pupils, with pre-school children free. The bus takes transport IC cards as well as cash.
Before you go
Check before travelling. As of 20 August 2026 the cave is closed after damage from Typhoon 15, with no reopening date announced; while it is shut the operator is opening the Ryusen Shindo Science Museum opposite free of charge, from 8:30 to 16:00, and posts reopening news on the official site. Heavy rain has forced the cave shut before, because the underground lakes rise into the walkway. Inside, the route is wet throughout and includes a long flight of stairs.
Another way
By car the run from Morioka on Route 455 takes a little under two hours, and from Miyako on the Sanriku coast about an hour. There is a parking area at the park by the entrance.
After you get off
The Ryusendo-mae stop sits on the road beside the park; the ticket gate is a short walk up along the river.