World Longest Sea Caves

Updated 08/15/2026

Original list compiled by Dave Bunnell, 1998 then continued by Bob Gulden with frequent updates and corrections by Dave Bunnell.

Send updates and corrections to Cavemonpaul at hotmail.com

Copyright 2026 NSS Geo2, Paul Burger NSS 26452, FE, CM
Do not ask for cave locations, I will not give them out.

Longest column61.5 metersTham Sao Hin, Thailand
Tallest unitary stalagmite72.76 metersYuLongdong, Guangxi Province, China
Tallest stalagmite in a cluster70 metersHang Son Doong, Vietnam
Longest free-hanging stalactite28 metersGruta do Janelao, Brazil
Longest single soda straw9.13 metersWonder Cave, Gunung Mulu, Malaysia
Longest soda straw grouping9.03 meters plus several over 8 metersUnnamed cave, Mexico
Tallest gour (rimstone dam)22 metersActun Kotob, Belize
Longest single gour in a cave61 metersXe Bang Fai Cave, Laos
Longest single gour, formed on the surface (1) 610 meters longWadi Sannur Cavern, Egypt
20 meters high
Longest connected gour series400 metersTinas Tepe Magara, Turkey
Flowstone cascade with greatest vertical extent150 metersNeverland to Dead Sea,Lechuguilla Cave, New Mexico
Longest continuous formation, white calcite crust in a stream channel12+ miles surveyed, continues on...Snowy River Passage, Fort Stanton Cave, New Mexico (as of february 2026)
Longest gypsum flower petal (supported)1.98 metersDouble Bopper Cave, Arizona, USA
(1) Wadi Sannur is a rare type of cave formed by roofing over of a giant surface gour at its spillover point.
The gour was formed by a large thermal spring.
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