North America · United States
Florida Keys — Key Largo & Islamorada
Warm shallow reefs and famous wrecks a short boat run from Key Largo and Islamorada
Photo: NOAA (Maya Walton) · Public domain
The Upper Keys, from Key Largo down to Islamorada, sit along the third-largest barrier reef system in the world, with warm, calm, shallow spur-and-groove reefs like Molasses and French Reef reached by day boat. Divers see sea turtles, nurse and reef sharks, groupers and stingrays over the coral; offshore, the 155-metre Spiegel Grove (510 feet) sits upright with her top deck at 18 m. The bronze Christ of the Abyss statue at Key Largo's Dry Rocks is among the most-dived sites in North America. The Vandenberg and the Lower Keys reefs are dived from Key West, about 150 km further southwest.
About diving in Florida Keys — Key Largo & Islamorada
A Keys diving day is short and boat-based. Charters run two-tank morning trips from canal-side docks in Key Largo and Islamorada, with the reef line usually well under an hour offshore, and afternoon or night trips fill the rest of the schedule. Boats tie into sanctuary mooring buoys instead of anchoring, so each dive begins from a fixed line and is worked around it. Almost every dive here starts from a boat, and most visitors treat the charter schedule as the whole plan.
The reef structure repeats down the chain. Coral fingers run seaward with sand channels between them, so navigation is largely a matter of following a groove out and a spur back, and depth changes are gentle enough that bottom times run long. Inshore of the reef line, scattered patch reefs in the shallows give crews somewhere workable when wind blows out the outer sites. The sunken ships sit further offshore and deeper than the coral, in more open water where current matters more.
What this area does well is volume and ease. Reef dives mostly run 9 to 15 m, so a diver can log several a day without a demanding schedule. Much of the best coral lies inside John Pennekamp Coral Reef State Park, the first underwater park in the United States, and in the sanctuary's preservation areas such as Molasses Reef and Key Largo Dry Rocks, where fishing and collecting are banned and touching or standing on coral is not allowed. The ships break the pattern: the Spiegel Grove's top deck lies at 18 m and her hull at 41 m, and she needs an Advanced card.
It suits new divers, mixed groups where some people only snorkel, and anyone stacking certifications, since training runs on the same boats and the Overseas Highway allows a change of towns without a change of flights. It also rewards repeat visitors who like unhurried reef photography. Divers set on the Vandenberg or the Lower Keys reef line should base in Key West, about 150 km further southwest; Looe Key is dived from Big Pine Key. Divers after walls or dependably long sightlines should look elsewhere, because visibility moves with wind and run-off and the terrain is gentle by design.
Best time to dive Florida Keys — Key Largo & Islamorada
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Season | Fair | Fair | Good | Prime | Prime | Prime | Prime | Prime | Good | Good | Good | Fair |
| Sea surface | 24°C75°F | 24°C75°F | 25°C77°F | 26°C79°F | 28°C82°F | 29°C84°F | 30°C86°F | 31°C88°F | 30°C86°F | 28°C82°F | 26°C79°F | 25°C77°F |
| Daytime high | 26°C79°F | 26°C79°F | 28°C82°F | 29°C84°F | 30°C86°F | 31°C88°F | 32°C90°F | 32°C90°F | 31°C88°F | 30°C86°F | 28°C82°F | 27°C81°F |
| Rain | 43 mm1.7 in | 37 mm1.5 in | 34 mm1.3 in | 76 mm3.0 in | 130 mm5.1 in | 207 mm8.1 in | 167 mm6.6 in | 192 mm7.6 in | 203 mm8.0 in | 131 mm5.2 in | 75 mm3.0 in | 54 mm2.1 in |
| Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|
| Fair | Fair | Good | Prime | Prime | Prime |
| Sea surface | |||||
| 24°C75°F | 24°C75°F | 25°C77°F | 26°C79°F | 28°C82°F | 29°C84°F |
| Daytime high | |||||
| 26°C79°F | 26°C79°F | 28°C82°F | 29°C84°F | 30°C86°F | 31°C88°F |
| Rain | |||||
| 43 mm1.7 in | 37 mm1.5 in | 34 mm1.3 in | 76 mm3.0 in | 130 mm5.1 in | 207 mm8.1 in |
| Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|
| Prime | Prime | Good | Good | Good | Fair |
| Sea surface | |||||
| 30°C86°F | 31°C88°F | 30°C86°F | 28°C82°F | 26°C79°F | 25°C77°F |
| Daytime high | |||||
| 32°C90°F | 32°C90°F | 31°C88°F | 30°C86°F | 28°C82°F | 27°C81°F |
| Rain | |||||
| 167 mm6.6 in | 192 mm7.6 in | 203 mm8.0 in | 131 mm5.2 in | 75 mm3.0 in | 54 mm2.1 in |
2011–2025 averages. Sea surface: NOAA Coral Reef Watch, measured at the surface, so deeper water can run colder. Daytime high and rain: NASA POWER.
April to August is the prime stretch, with the calmest seas of the year and water that climbs through the high 20s °C to a summer peak of about 30 °C. September to November stays good and quiet once summer crowds leave, but falls inside the June-to-November hurricane season, and November brings the first cold fronts. December to February is the weakest run for sea state, not for clarity: winter often brings the best visibility of the year, but cold fronts raise wind and chop for a day or two at a time and can cancel outer-reef trips, while the water drops to its annual low of about 24 °C. March is the turn, still cool but settling, and busy with spring-break divers.
Best months: April, May, June, July, August
Florida Keys water temperature and weather by month
The sea surface runs from 24 °C (75 °F) in January to 31 °C (88 °F) in August. Most rain falls from May to October, peaking at about 210 mm (8.3 in) in June; it stays largely dry from December to March. Daytime highs reach 32 °C (90 °F) in August and drop to 26 °C (79 °F) in January. The coldest water here is about 23 °C (73 °F), so pack a 5 mm suit.
Dive types & marine life
Reef fish carry the year: grunt and snapper stacked under the ledges, parrotfish and angelfish over the coral heads, morays in the grooves, barracuda off the mooring lines and nurse sharks tucked beneath the overhangs. The deeper ships hold the bigger grouper and jacks. Turtles turn up in any month, and the calm April-to-August stretch brings the clearest water and summer clouds of silversides.
- Reef
- Wreck
- Drift
- Night
- Reef sharks
- Sea turtles
- Groupers
- Barracuda
- Trevally & jacks
- Reef fish swarms
- Stingrays
Best dive sites in Florida Keys — Key Largo & Islamorada
- 1
Molasses Reef
Outer spur-and-groove reef off Key Largo with 32 mooring buoys, dived from 2 to 18 m.
- 2
USS Spiegel Grove
155 m Navy ship (510 ft) sunk in 2002; deck at 18 m, hull at 41 m, Advanced only.
- 3
Christ of the Abyss
Bronze statue on Key Largo Dry Rocks in about 7.6 m, lowered in 1965; for snorkel or scuba.
- 4
French Reef
Swim-through caves and arches in 5–12 m, partly inside a sanctuary preservation area.
- 5
SS Benwood
Norwegian freighter lost in a blacked-out wartime collision in 1942, broken up in 8–14 m.
- 6
USCGC Bibb
100 m Coast Guard cutter (327 ft) sunk off Key Largo in 1987, lying to 40 m.
- 7
Eagle Wreck
82 m freighter (269 ft) sunk off Islamorada in 1985 in 21–34 m, split by Hurricane Georges.
Site guides
A nine-foot bronze figure standing in 7.6 m of water
Reef
A sand pit at 15 m (50 ft) leading out to a 27 m (90-foot) drop-off
Wreck
A freighter cut in half by Hurricane Georges in 1998
Cave & cavern
A long, narrow swim-through at the south end of Molasses
Reef
Winding channels and swim-throughs inside a protected reef
Reef
A reef crest that breaks the surface at low tide
Cave & cavern
A swim-through in the French Reef protected area
Reef
A sand channel running through spur-and-groove coral
Thirty-two mooring buoys along one spur-and-groove reef
Reef
The south end of Molasses and the start of the reef drift
Reef
A shallow patch reef where turtles, sharks and rays pass
Two high ledges and a staghorn and elkhorn outplanting site
Wreck
A blacked-out wartime collision, now a 14 m wreck dive
Wreck
Coast Guard cutter on her side at 40 m, in constant current
155 m (510 ft) of Navy dock landing ship, upright since 2005
How to get to Florida Keys — Key Largo & Islamorada
Most people fly into Miami or Fort Lauderdale and drive the Overseas Highway; Key Largo is the first town in the chain and Islamorada the next, and each has its own charter fleet and makes a workable base. Diving is almost entirely day-boat, and a car is worth having. Key West, with its own airport, is the base for the Vandenberg and the Lower Keys, about 150 km further southwest.
Photos from Florida Keys — Key Largo & Islamorada
Matt Kieffer from London, United Kingdom · CC BY-SA 2.0
Jstuby · CC0
U.S. Department of Defense · Public domain
Symbiosis · CC BY 2.0
Dive videos
Dive Adventure | 4 Wrecks in Key Largo | USCG Duane, USCG Bibb, Spiegel, Benwood · Journeys of AnnaZach on YouTube
Diving The Florida Keys in 5K! Florida Keys Scuba Diving · Fintastic Films on YouTube
Questions divers ask
What is the best time to dive the Florida Keys?+
April to August, when the seas are calmest and the water warmest, up to about 30 °C. December to March brings cooler water and occasional windy days from cold fronts, though often the clearest water of the year, and September and October fall inside hurricane season.
What certification do I need to dive Key Largo?+
Open Water covers the reefs, which mostly run 9 to 15 m, and the shallow Benwood wreck in 8 to 14 m. The Spiegel Grove, the Bibb and the Eagle lie between about 18 and 40 m and need Advanced certification, and going inside the Spiegel Grove needs wreck training as well.
Should divers base in Key Largo or Key West?+
Key Largo and Islamorada for the densest reefs, the clearest water on the reef tract and the Spiegel Grove; Key West for the Vandenberg and the Lower Keys reef line. They are about 150 km apart on the Overseas Highway, and Looe Key is dived from Big Pine Key in between.
What are the rules for diving the Florida Keys marine sanctuary?+
Diving and snorkelling are allowed in the sanctuary preservation areas, but fishing and collecting are banned there, and touching or standing on coral is prohibited. Boats tie into mooring buoys rather than anchor on the reef.
How do divers get to Key Largo?+
Fly into Miami and drive south on the Overseas Highway (US-1) for about an hour. Key Largo is the first town in the chain and Islamorada the next, and a car is worth having since the charters leave from docks along both.
Sources
- Sanctuary Preservation Areas — NOAA Florida Keys National Marine Sanctuary
- Florida Reef — Wikipedia
- John Pennekamp Coral Reef State Park — Wikipedia
- Molasses Reef — Wikipedia
- USS Spiegel Grove — Wikipedia
- Christ of the Abyss — Wikipedia
- SS Benwood — Wikipedia
- Key West: climate — Wikipedia
- Diving Florida Keys – Key Largo — PADI
- Best Time to Scuba Dive in Key Largo — Scuba Fun Florida
- Scuba Diving in Key Largo — Key Largo Scuba Diving
Photo credits
- Sunlit reef landscape with a school of fish over coral at Conch Reef in the Florida Keys by NOAA (Maya Walton), Public domain, via Wikimedia Commons
- Hawksbill turtle gliding over a coral reef in the Florida Keys by Matt Kieffer from London, United Kingdom, CC BY-SA 2.0, via Wikimedia Commons
- Diver examining a star coral colony at Molasses Reef in the Florida Keys by Jstuby, CC0, via Wikimedia Commons
- Navy diver photographing marine life on a training dive off Key West, Florida by U.S. Department of Defense, Public domain, via Wikimedia Commons
- Spotted scorpionfish camouflaged on coral in the Florida Keys by Symbiosis, CC BY 2.0, via Wikimedia Commons
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In The Logbook
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- DPV diving: what an underwater scooter changesGear & kit · 10 min read
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Shallow Sanctuary patch reefs and the intact Thunderbolt wreck at 37 m
The Vandenberg wreck plus shallow sanctuary reefs
Goliath groupers over 200 kg mass on the wrecks to spawn each August
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The Gulf of Mexico's largest reef complex, off a working port