Ehime · Imabari · OshimaNo.1310★★Open in map →

Noshima Castle Ruins

historyOff the trail — and worth it

A small uninhabited island off Oshima that was once, in its entirety, a castle: the base of the Noshima Murakami, a seafaring clan remembered as pirates. Today you see it from a tidal-current boat that tours the waters around it.

FromImabari Station
Two buses, one changeExpress bus + island bus
Get off atMurakami Suigun Hakubutsukan (Oshima island bus)
From there
Noshima Castle Ruins

Directions ↗

The sweet spot

Noshima is a national Historic Site and the heart of the Murakami pirate story, so it is no secret. What catches first-timers out is that you usually cannot walk on it. There is no scheduled boat, and landing is limited to organised tours. This is a castle you read from the water.

Where it is

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What to look for

Tidal races around Noshimaさかおり / CC BY-SA 4.0

Murakami Kaizoku Museumthe city museum on the Miyakubo shore, showing excavated finds, with a third-floor viewing room over the sea
Tidal races around Noshimacurrents of up to 10 knots, about 18 km/h, that once served the castle as a moat
Noshimathe castle island itself, with round post holes cut into its shoreline rocks, thought to have held piers
Taizaki-jimathe islet facing Noshima's south side, its flattened top once used as an outwork
Hakata-Oshima Bridgethe Shimanami Kaido span, seen from below on the boat

How to actually get there

Imabari Ekimae → Ishi-bunka-koen (Setonaikai Kotsu express bus).
Ishi-bunka-koen → Murakami Suigun Hakubutsukan stop (Oshima island bus).
Bus stop → Murakami Kaizoku Museum and the boat counter (on foot, about a minute).
Board the tidal-current boat for the waters around Noshima.

Express bus, then the Oshima island bus: From the Imabari Ekimae stop, take the Setonaikai Kotsu express bus for Oshima, Hakata-jima and Omishima, and get off at Ishi-bunka-koen. Change there to the Oshima island bus and ride to the Murakami Suigun Hakubutsukan stop. The operator publishes timetables for both lines, so plan the change before you set out.
Back to Imabari: Take the island bus back to Ishi-bunka-koen and change to an express bound for Imabari. You need the island bus to reach the express, so check its last run before you board the boat.

Directions from my location (Google Maps) ↗

About the place

Noshima lies in the narrow channel between Oshima and Hakata-jima, in the Shimanami island chain. It is only about 720 metres around, yet the whole island was shaped into a castle. Its summit was levelled into the main enclosure, and terraces step down around it. Nobody lives on Noshima today. A tidal-current boat runs from the shore in front of the Murakami Kaizoku Museum and loops through the waters around the island. From the deck you can see why it was so hard to attack: as the tide runs, the sea churns into swirls and bulges.

How to enjoy it

Start at the museum to get your bearings, then walk out to the boat. Sailings leave on the hour from 9:00 to 15:00, and each trip lasts about 40 minutes. Rough weather can cancel a sailing even just before departure, so keep the day flexible.

Background & history

The Noshima Murakami were one of three Murakami houses, alongside those of Innoshima and Kurushima. Excavated finds and old records point to their use of the island from the fourteenth century. They held the central, shortest sea route through the islands. Passing ships paid them a toll and, in return, received a flag pass and pilots for safe passage. That role ended with Toyotomi Hideyoshi's 1588 edict against piracy. The island became a national Historic Site in 1953, and the Murakami story is now recognised as Japan Heritage.

Before you go

Cash: As listed in October 2026: museum admission ¥310 for adults and free for high-school age and under; the tidal-current boat ¥1,800 for adults and ¥1,000 for primary-school children. Parking at the museum is free.
Good to know: The museum closes on Mondays (the next weekday when Monday is a holiday) and from 29 December to 3 January. Imabari City lists Monday as the boat's day off too. There is no scheduled boat to Noshima itself; landing tours are run by a separate operator, so check whether and when they run.
Another way: From the Honshu side, take the Shimanami Liner highway bus to Oshima BS and change to the Setonaikai Kotsu island bus for the Murakami Suigun Hakubutsukan stop. Drivers can leave the expressway at Oshima-kita IC coming from Honshu, or at Oshima-minami IC coming from Imabari.
After you get off: The stop keeps the museum's former name. The museum and the boat counter, inside the Noshima Suigun restaurant building in front of it, are about a minute's walk away.