Martz Sink
Certified cave and cavern diving only: Florida State Parks diving rules [2] (Park-wide rule; no site-specific category published for Martz Sink.). These categories are the named scheme's own; they describe the training a site calls for.
A sinkhole in Madison Blue Spring State Park that Florida State Parks describes as a way for trained cave divers to enter the Madison Blue cave system.
Florida State Parks mentions Martz Sink as a place where cave divers can descend into the Madison Blue cave system, and stresses that specialised cave training is essential. The same park rules apply as at the main spring: certified cave or cavern divers only, teams of two or more, and dives finished an hour before sundown.
The park pages give no depth, size or directions for the sink, so check with park staff on arrival.
The environment
A sinkhole opening into the Madison Blue cave system; no published measurements.
Other entrances to Madison Blue Spring cave system
For orientation, not navigation. Hollow dots are approximate.
Every fact on this page, with its source (5)
| Fact | Status | Source |
|---|---|---|
| Florida State Parks invites trained cave divers to descend at Martz Sink into the park's cave system and requires divers to work in pairs and finish at least one hour before sundown. | Verified | [1] |
| The park is open to certified cave and cavern diving only. | Verified | [2] |
| Park rules require sign-in, at least two divers, diving within certification, no DPVs, and completion one hour before sunset. | Verified | [2] |
| Park admission is $4 to $5 per vehicle.Read 2026-10-14. | Verified | [3] |
| The park is open from 8 a.m. to sunset.Read 2026-10-14. | Verified | [3] |
Verified: stated by an official or primary source we opened. Reported: from a secondary source only. Sources conflict: the note gives both versions. May be out of date: the newest source we found is old.
Written in our own words from the sources above. Report a correction