Longest underwater caves
Ranked by reported survey data.
| # | Cave | Location | Length | Source |
|---|---|---|---|---|
| 1 | Sistema Ox Bel Ha | Tulum, Quintana Roo, Mexico | 541,791 m | CINDAQ 2025 Annual Report Primary source |
| 2 | Sistema Sac Actun | Quintana Roo, Mexico | 379,569 m | QRSS Long Underwater Caves Secondary source Provided by: Alvarez/Nava/Reato/Picard |
| 3 | Sistema K'oox Baal | Quintana Roo, Mexico | 123,000 m | Facebook Report Primary source Provided by: Robbie Schmittner |
| 4 | Wakulla Cave System | Leon/Wakulla, Florida, USA | 72,171 m | Cave-Exploring World Long Caves Secondary source Provided by: Casey McKinlay e-mail |
| 5 | Sistema Xunaan Ha | Quintana Roo, Mexico | 57,344 m | QRSS Long Underwater Caves Secondary source Provided by: Quiet Diver Team |
| 6 | Sistema Toh Ha | Tulum, Quintana Roo, Mexico | 47,746 m | QRSS Long Underwater Caves Secondary source Provided by: Berni/Sieff |
| 7 | Sistema Zapote-Camilo Also: Cenote Zapote, Sistema Camilo | Quintana Roo, Mexico | 40,169 m | QRSS Long Underwater Caves Secondary source Provided by: Coffield-Feith/ Bulman |
| 8 | Sistema Nohoch Kai | Tulum, Quintana Roo, Mexico | 33,505 m | QRSS Long Underwater Caves Secondary source Provided by: Proyecto Nohoch Kai/ Schmittner/ Gugermeier |
| 9 | Sistema Caterpillar | Quintana Roo, Mexico | 28,253 m | QRSS Long Underwater Caves Secondary source Provided by: DRSS/QDT |
| 10 | Sistema Sand Crack | Tulum, Quintana Roo, Mexico | 26,746 m | QRSS Long Underwater Caves Secondary source Provided by: Quiet Diver Team/DRSS |