Kashiwajima is a tiny island off the far southwestern coast of Kochi, famous for water of extraordinary clarity — so transparent that moored boats appear to hover above the seabed as if floating in air. Where the warm Kuroshio current meets cooler waters, an exceptional diversity of marine life gathers, and the island is ringed by coral reefs home to a huge variety of tropical and temperate fish. This makes it one of the best places in mainland Japan for snorkelling and diving, with easy access to vivid underwater scenery just offshore. Remote and unspoiled, connected to the mainland by a short bridge, Kashiwajima rewards the long journey with some of the clearest, most life-filled sea in the country.
🗓️ At a Glance
| Location | Kashiwajima, Shimanto Town |
| Hours | Dives/snorkel tours by booking |
| Admission | Activities vary |
| Time needed | Half to full day |
| Best time | Summer to autumn for warm, clear sea |
What to See & Do
- Water so clear boats seem to float on air.
- Coral reefs rich with tropical and temperate fish.
- Snorkelling and diving in vivid underwater scenery.
- A remote, unspoiled island reached by a short bridge.
Combine Your Visit
- Combine with Cape Ashizuri in the far south.
- Pair with the Shimanto River on the way.
- Read our Kochi overview .
Getting There
- By car: essential, via a long drive to Kochi’s far southwest.
- By bridge: the island is linked to the mainland by road bridge.
Tips
Come in summer or autumn when the sea is warm and clearest for snorkelling and diving, and book tours or gear rental ahead as this is a remote spot with limited facilities. Allow for the long drive and consider staying overnight nearby, bring reef-safe sunscreen and water shoes, and check conditions as visibility depends on weather and tides.
