The Tubbataha Reefs are a double atoll in the middle of the Sulu Sea, 150 km southeast of Puerto Princesa, completely uninhabited apart from a rotating park ranger station. They are the diving jewel of the Philippines: 100,000 hectares of pristine coral, with sharks (reef, grey, occasionally hammerhead), manta rays, schooling jacks and barracuda, and some of the highest fish biomass measured anywhere in Asia.
Access is by liveaboard only, in a short season from mid-March to mid-June when the seas are calm. Trips are six to seven nights, cost several thousand dollars, and need to be booked many months ahead. Most boats leave from Puerto Princesa.