United States · Florida
Florida Keys
Warm-water reef season before winter cold fronts become more common.
The Florida Keys offer the US's most accessible reef and wreck diving — the Christ of the Abyss statue, the USS Spiegel Grove and USS Vandenberg artificial reef wrecks, plus living coral reef tract from Key Largo to Key West.
Good season
Year-round; May–September is warmest. Hurricane risk June–November.
Trip duration
3–7 nights with rental car along the Keys.
Dive style
Boat diving on reef and wreck; mild-to-moderate current.
Dive level
Open Water for most reef; Advanced for the deeper wrecks (30m).
Reef health
What you’ll actually findThis reef has lost most of its live coral. Fish life and topography may still be worth diving, but expect a very different reef from the older photos.
Coral reef health
How is this calculated?On current trend, no live coral by ~2036. Losing about 1.1% cover per year — roughly 12 years of reef left to see if nothing changes.
Heat stress right now
No abnormal heat right now. Corals stay coloured.
NOAA Coral Reef Watch · updated May 2026 · 0 °C-week heat dose
What to expect on a dive
Florida Keys reefs have lost the majority of their hard coral over two decades and were hit hard by 2023's marine heatwave. Wrecks and fish life still excellent.
Sources, methodology, and the raw numbers
Raw observed numbers
- Coral cover: 13% (survey Sep 2024, NOAA NCRMP Florida Keys monitoring)
- Bleached: 28%
- Recent mortality: 13%
- Florida Keys — observed condition reflects the severe decline regional pattern.
Raw thermal numbers
- NOAA CRW alert level: No stress
- Degree Heating Weeks: 0 °C-wk
- SST anomaly: +1.9 °C
How we summarise this
Observed coral cover, bleaching, and mortality come from named in-situ surveys with a stated date and method — they describe one snapshot of one reef and do not extrapolate to neighbouring sites. Current thermal stress is satellite-derived from NOAA Coral Reef Watch at ~5 km resolution; it indicates risk, not observed coral damage. We deliberately separate observed condition, current thermal stress, and projection — and we never publish a projection without a documented model and uncertainty.
Sources
- NOAA National Coral Reef Monitoring Program — NOAA Coral Reef Conservation Program
- NOAA Coral Reef Watch — U.S. National Oceanic and Atmospheric Administration
- AIMS Long-Term Monitoring Program — Australian Institute of Marine Science
- Global Coral Reef Monitoring Network — GCRMN / ICRI
- Atlantic and Gulf Rapid Reef Assessment — AGRRA Program / Perry Institute for Marine Science
- Reef Check — Reef Check Foundation
- NOAA CoastWatch / OceanWatch — NOAA NESDIS / STAR
- Allen Coral Atlas — Arizona State University Center for Global Discovery and Conservation Science
- Great Barrier Reef Marine Park Authority — Australian Government
- International Coral Reef Initiative — ICRI Secretariat
- Reef Life Survey — Reef Life Survey Foundation
- NASA PO.DAAC — NASA Jet Propulsion Laboratory / Caltech
- Copernicus Marine Service — Mercator Ocean International for the European Union
- NASA Ocean Color (OB.DAAC) — NASA Goddard Space Flight Center / Ocean Biology Processing Group
- Argo float network — International Argo Program / UCSD
- CoralWatch — University of Queensland
- IMOS / AODN — Integrated Marine Observing System / Australian Ocean Data Network
- WRI Reefs at Risk Revisited — World Resources Institute
- Ocean Health Index — OHI partnership (Conservation International + UCSB + NCEAS)
- IPCC Special Report on the Ocean and Cryosphere (SROCC) — Intergovernmental Panel on Climate Change
- GOA-ON — Global Ocean Acidification Observing Network — GOA-ON Secretariat + IOC-UNESCO
- HAEDAT — Harmful Algae Event Database — IOC-UNESCO Intergovernmental Panel on Harmful Algal Blooms
- NCEI Marine Microplastics — NOAA National Centers for Environmental Information
Reef condition changes year to year. If you visit, consider supporting responsible-travel and conservation operators on the ground.
Pressure on this reef
Protection · fishing · what you can doProtected-area status
Strict MPAInside a strict marine protected area with active enforcement.
Fishing pressure
Moderate fishing pressureDominant pressures
- agricultural runoff from south Florida
- SCTLD
- warming
- tourism
4 Green Fins-verified operators known at this location.
What you can do
Florida Keys National Marine Sanctuary protects the reef but can't protect the water flowing from the Everglades. Choose restoration-affiliated operators and pay the sanctuary fee.
Protection status sourced from Protected Planet / WDPA and refined with Marine Protection Atlas. Fishing pressure proxy is Global Fishing Watch AIS data. See the methodology for what these sources can and can’t prove.
Pollution & water-quality
What divers should knowSCTLD coral disease outbreak
SEVERESince 2014
Stony coral tissue loss disease has affected over half of Florida's reef-building coral species. Brain corals, star corals, and pillar corals have been hit hardest. Active treatment programs are ongoing at major sites.
Agricultural runoff from south Florida
CONCERNINGSince ongoing
Nutrient-laden freshwater from sugar plantations and the Everglades chronically degrades reef-flat water clarity, especially after summer rains.
What this means for your trip
Choose offshore sites and wall dives over inshore patch reefs for the best visibility. Many operators participate in coral-restoration nurseries — ask about joining a fragment-outplanting dive.
Dive sites here
6 curatedUSS Vandenberg
159 m former missile-tracking ship scuttled off Key West in 2009 — the second-largest artificial reef in the world. Massive radar dishes, gu…

Christ of the Abyss
Bronze statue of Christ standing in 8 m of water on Dry Rocks reef in Key Largo, placed in 1965 and now coated in coral and sponges. Easy sh…

USS Spiegel Grove
510-foot Thomaston-class dock landing ship sunk as an artificial reef 6 miles off Key Largo in 2002 — one of the largest intentionally scutt…

Molasses Reef
Spur-and-groove coral reef 6 miles off Key Largo, anchored by an 1880s wrought-iron light tower and routinely cited as one of the most visit…

Looe Key Reef
U-shaped spur-and-groove reef 5 miles south of Big Pine Key, named after the 44-gun HMS Looe — a British man-of-war that ran aground here in…

USCGC Duane
A 100 m Treasury-class US Coast Guard cutter scuttled 1 mile south of Molasses Reef off Key Largo on 27 November 1987 as an artificial reef.…
Gear
What to bringSite-specific add-ons
Some dive sites here call for extra gear. Check the individual site page for full context.
- Dive light — Interior compartments are dark and silt-prone. · USS Vandenberg
- Wreck-trained guide — Penetration sections require formal training. · USS Vandenberg
- Underwater camera — Iconic photo subject — even smartphone housings deliver here. · Christ of the Abyss
- SMB and reel — Gulf Stream current can push divers off the wreck during ascent; deploy a marker for boat pickup. · USCGC Duane
- Dive computer with deco modeling — Deck-level depth at 27-30 m and bottom time on the wreck routinely push recreational no-deco limits. · USCGC Duane
- Nitrox certification recommended — EAN32 significantly extends bottom time at the deeper deck and stern. · USCGC Duane
What divers say
“The Vandenberg is one of the great Americas wreck dives. Two days isn't enough to see all of it.”