Devil's Den - Florida Keys
Devil's Den is an interesting change of pace from the usual reef dives in the Keys. We’re talking about a prehistoric spring, an underground cavern that opens up into cool, clear water. You drop in from an opening at the top, which lets in a surprising amount of light for a cave, illuminating the rock formations. It’s a pretty easy dive, mostly about buoyancy control as you explore the space. We’ve spotted the occasional Eastern Mosquitofish darting about, and rumor has it an Atlantic Ridley has been seen, though we haven't been so lucky yet. It's a solid pick for divers looking for something a bit different, a chance to explore a unique geological feature without the challenges of a full-on cave system.
- Location
- Florida Keys, United States, North America
- Coordinates
- 29.407494, -82.476430
- Type
- cave
Marine Protected Area: Waccasassa Bay State Preserve
Best Time to Dive in Florida Keys
The warmest water temperatures in Florida Keys occur in July, averaging 31.5°C (up to 34.8°C). The coolest conditions are in January at 19.3°C.
Monthly Water Temperatures
- January: 19.3°C (air: 18.5°C)
- February: 20.5°C (air: 21.6°C)
- March: 23.1°C (air: 22.4°C)
- April: 25.5°C (air: 24.3°C)
- May: 27.8°C (air: 25.9°C)
- June: 30.2°C (air: 27.5°C)
- July: 31.5°C (air: 28.3°C)
- August: 31.5°C (air: 28.3°C)
- September: 30.2°C (air: 27.3°C)
- October: 27.3°C (air: 26.0°C)
- November: 24.1°C (air: 22.3°C)
- December: 20.9°C (air: 19.8°C)
Nearby Dive Sites in Florida Keys
- 1 Girón
- 9-foot Stake (reef)
- Ajax Reef (reef)
- Alexander Springs
- Alligator Reef (reef)
- Anglin Pier Ledge - 10m (reef)
- Anglin’s Pier Reef - 5-15m (reef)
- Aquarium - 10m
- Ball and Chain - 11m
- Banana Patch Reef - 10m (reef)
- Barracuda Dive Centre
- Beach House - 19m
- Blue Grotto Spring (cave)
- Boynton Comb Reef (reef)
- Boynton Ledges - 21m (reef)
Nearest Dive Centres to Devil's Den
Marine Life in Florida Keys
Home to 91 recorded species including 69 reef fish, 6 sharks & rays, 3 other, 3 hard corals, 2 sea snails & nudibranchs, 2 sea urchins.
Notable Species
- Bull Shark (Carcharhinus leucas) - Sharks & Rays
- Blacktip shark (Carcharhinus limbatus) - Sharks & Rays
- Cowfish (Rhinoptera bonasus) - Sharks & Rays
- Cowfish (Tursiops truncatus) - Whales & Dolphins
- Blacknose shark (Carcharhinus acronotus) - Sharks & Rays
- Great hammerhead (Sphyrna mokarran) - Sharks & Rays
- Prodigal Son (Rachycentron canadum) - Reef Fish
- Eastern Mosquitofish (Gambusia holbrooki) - Reef Fish
- Sailfin Molly (Poecilia latipinna) - Reef Fish
- Least Killifish (Heterandria formosa) - Reef Fish
- Florida Cone (Conus anabathrum) - Sea Snails & Nudibranchs
- Bream (Lagodon rhomboides) - Reef Fish
- Common mojarra (Eucinostomus gula) - Reef Fish
- Bonnethead Shark (Sphyrna tiburo) - Sharks & Rays
- Pigfish (Orthopristis chrysoptera) - Reef Fish
- Lined Sole (Achirus lineatus) - Reef Fish
- Inshore Lizardfish (Synodus foetens) - Reef Fish
- Freshwater Flounder (Trinectes maculatus) - Reef Fish
- Herring (Harengula jaguana) - Reef Fish
- American Gulf Pipefish (Syngnathus scovelli) - Reef Fish
Recommended Packing List for Devil's Den
Based on average water temperature of 26.0°C, currents 1 cm/s.
- Shorty or Rashguard - warm 26°C water needs minimal exposure protection
- Mask - essential for every dive
- Fins
- BCD - buoyancy compensator
- Regulator - your most safety-critical piece of gear
- Dive Computer - tracks depth, time, and NDL
- Surface Marker Buoy (SMB) - essential for boat pickups
- Dive Torch - useful for crevices and colour at depth
- Underwater Camera - capture your diving memories