Philippines

The Philippines has no single cave-diving province. Submerged systems appear across Palawan, Cebu, Bohol, Negros, Dinagat, Surigao del Sur and Siargao as marine caves, brackish dissolution caves, deep springs, tidal cenotes, lake-to-sea tunnels and sumps inside much larger karst landscapes.

The national cave-diving story is comparatively young but strongly Filipino: local explorers, community access, training, conservation and scientific survey developed together from the 1990s onward.

Pawod in Mactan is historically central. Dr Alfonso “Doc” Amores began exploring it in the early 2000s, and it became a local training cave and gathering point for the emerging Philippine cave-diving community. A 2016 assessment mapped 258.42 m of directionality and documented brackish conditions, saltwater intrusion and urban aquifer stress.

Casili is a tight freshwater exploration cave with no-mount/sidemount restrictions and a 2011 endpoint around 30.5 m. Tuble near Moalboal adds a deep tidal marine cave with restrictions, while Marigondon remains a lighter cavern-training environment.

Hinatuan Enchanted River is the deepest and best-documented Philippine cave system in the current public record. Alex Santos made an early exploration in 1999; later work with Dr Alfonso Amores, Bernil Gastardo and others reached the 80-87 m class in a tidal, brackish system with powerful flow.

Dr Amores died during a 17 June 2014 expedition after a medical emergency in the cave. Exploration later shifted strongly toward science through the HERUCS source assessment, combining cave diving with water chemistry, biology and conservation.

Pamutuanan near Lianga exceeds 450 m explored and alternates partially flooded, submerged and air-pocket sections. Tarusan remains an unfinished strong-outflow spring cave beyond 31 m depth.

FCD’s 2007 Bohol work established that the island’s cave pools and springs include real submerged karst. The official Bohol Global Geopark distinguishes the tourist cave pools from unresolved deeper springs such as Canawa, where repeated dives have not established the bottom or source.

Hinagdanan has supported biological cave research but should not be treated as a public full-cave venue without explicit authorization. Mabinay, Negros Oriental, has hundreds of known caves and current reports of underwater exploration, making it a strong future sump province pending formal survey publication.

Alex A. Santos — pioneering Filipino technical/cave diver; Paglugaban and early Hinatuan.
Dr Alfonso Y. “Doc” Amores — Pawod pioneer and major Visayas/Mindanao explorer.
Bernil H. Gastardo — FCD co-founder, exploration and conservation work.
Jake Miranda — FCD co-founder; Bababu, Pamutuanan, Siargao and cave-management advocacy.
Lyndon Cubillan, Xavier Garay, Ivar Almhjell — major Dinagat/Surigao exploration roles.
Filipino Cave Divers — national exploration/survey/conservation group.
DENR/BMB, National Cave Committee, PCSD, PCSSD — key management and regulatory institutions.

Surigao del Sur: Hinatuan, Tarusan, Pamutuanan and additional springs suggest a broader groundwater province.
Dinagat: Bababu proves sea-to-lake submerged systems exist.
Siargao: reversible cenotes imply a hidden anchialine network.
Bohol: Canawa and interior springs remain unresolved.
Mabinay / Negros and Samar: giant dry-karst landscapes may contain future sump projects.
Palawan: marine/freshwater interfaces remain strong research targets under strict protection.
National inventory: a unified underwater-cave GIS/survey layer would transform both exploration and conservation.