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Kashiwajima Island

islanddivingsnorkelingsea turtlesKuroshio Current

Kochi · Tosashimizu

32.7833°N, 132.5667°E

Kashiwajima is a small island off the coast of Tosashimizu, surrounded by some of the clearest water in Japan. The island sits in the path of the warm Kuroshio Current, which brings tropical fish, coral, and exceptional underwater visibility (often 20+ meters). Diving and snorkeling here reveal a world of butterflyfish, wrasse, sea turtles, moray eels, and seasonal schools of barracuda. The water temperature remains above 20°C even in winter, making it a year-round dive destination.

The island itself is tiny — you can walk around it in 30 minutes. There are no hotels, just a few guesthouses, dive shops, and a small fishing port. The vibe is quiet, unhurried, and focused entirely on the ocean. Most visitors come for the day, diving or snorkeling in the morning and returning to the mainland by evening.

Essential Information

Opening Hours

Island accessible 24 hours (bridge from mainland). Dive shops typically 8:00 AM – 5:00 PM. Glass-bottom boat tours: 9:00 AM – 4:00 PM (weather permitting). Minshuku guesthouse check-in from 3:00 PM.

Closed: Island always accessible. Dive shops and boat tours may cancel during rough seas and typhoon warnings (July–September is most unpredictable). Dive certification courses run April–October.

Entrance Fee

Island access free (bridge crossing). Guided scuba diving ¥12,000 for 2 dives (equipment included). Snorkeling gear rental ¥1,500. Glass-bottom boat tour ¥2,000. Minshuku from ¥8,000/night with meals.

Best Season

June–October for warmest water (24–28°C) and best visibility (20+ meters). May and November are cooler but less crowded. December–March is possible for experienced divers but seas can be rough.

Visit Duration

Day trip with snorkeling and island walk: 4–5 hours. Full dive day (2 dives + lunch): 6–7 hours. Overnight stay for multi-dive experience: 2 days.

Getting There

Access Information

Kashiwajima is by car from Tosashimizu City. The island is connected to the mainland by a short bridge. Dive shops offer gear rental and guided dives (¥12,000 for 2 dives). Snorkeling gear rental ¥1,500. Best season: May–October.

Insider Guide

Premium

**Diving:** Kashiwajima has 30+ dive sites, ranging from shallow reefs (10m) to deep walls (30m). The most famous site is 'Tatsukushi' — a coral-covered reef teeming with tropical fish. Dive shops in Kashiwajima offer guided dives with English-speaking guides (advance booking required). PADI certification courses also available. **Snorkeling:** For non-divers, snorkeling is excellent. The best snorkeling is off the island's southern coast, where shallow reefs (2–5m depth) are accessible from the beach. Rent gear at Kashiwajima Marine Park (¥1,500 for mask, fins, snorkel). Best visibility is on calm, sunny days. **Sea turtles:** Kashiwajima is known for sea turtle sightings. Green turtles and loggerhead turtles frequent the area, especially near the seagrass beds on the island's west side. Snorkeling in the early morning (7:00–9:00) increases your chances. **Glass-bottom boat:** If you prefer to stay dry, take a glass-bottom boat tour (¥2,000, 40 min). The boat departs from the island's port and cruises over coral reefs and rock formations. Turtles and large fish are often visible through the glass floor. **Best season:** June–October for warmest water and best visibility. May and November are slightly cooler but less crowded. Winter (December–March) is possible for experienced divers (wetsuit required), but seas can be rough. **Accommodation:** Stay on the island at Minshuku Kashiwajima (民宿柏島, from ¥8,000/night with meals) for the full experience — wake up to ocean views, dive in the morning, eat fresh-caught fish for dinner. Or stay in Tosashimizu and drive over for the day. **Getting there:** Rental car from Kochi is the easiest (3 hours via Route 56). Alternatively, take the bus from Kochi to Tosashimizu (2.5 hours), then taxi to Kashiwajima (20 min, ¥3,000).

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