Descend into the legendary 'Thuduk' underwater cave system linking Irabu and Shimoji islands — a once-in-a-lifetime dive through cathedral-lit caverns and swim-through arches in waters of extraordinary clarity. This is Okinawa's most coveted dive site.
What to expect
A small speedboat departs Irabu's marina and reaches the dive site in under 15 minutes. You slip into 25 °C water and follow your guide through the famous 'Nagama Anaa' passage — sunlight refracts through the cave mouth in stunning cathedral beams. The second tank takes you along the outer reef wall draped in sea fans and patrolled by white-tip reef sharks. Post-dive, a light bento lunch with Okinawan sea-salt onigiri is served on deck before the return.
Good to know
Advanced Open Water certification required; cavern sections are suitable for Open Water divers with a guide. Irabu Bridge is 20 mins from Hirara Port. Book at least one week ahead — this operator limits daily slots. Dry suit not needed; 3 mm wetsuit provided.
Sail there
Luxury cruises that call at Miyakojima — book through us, the fare is identical and your concierge stays on your side.