Key Largo vs Key West for Diving and Snorkeling: Which Base?

by Yannick SchrothOct 13, 202612 min read

Fort Jefferson on Garden Key, Dry Tortugas National Park, about 70 miles west of Key West: the Key West side of this comparison. An NPS archive slide; NPGallery dates it November 2003. Photo: NPS, Wikimedia Commons, public domain, cropped.

Rules, schedules and fees as of October 2026. Water figures are NOAA buoy-station averages; the periods and the caveats are in the water section below.

Key Largo's reefs are federal water, Key West's are state water, and the rules split there

This is the difference that matters most in Key Largo vs Key West, because it changes what a dive boat may do on the reef. Both towns dive the Florida Keys National Marine Sanctuary. NOAA rewrote the sanctuary's regulations in a final rule published on 17 January 2025 (90 FR 6104). On 3 March 2025 Governor Ron DeSantis certified that rule unacceptable, so it does not take effect in the part of the sanctuary that lies in Florida's state waters.

NOAA's own zone data, revised on 28 April 2026, settles which side each reef is on. Molasses Reef, The Elbow and the 146.9-square-mile Key Largo Management Area are marked “Within_State_Waters: No”. Sand Key, Rock Key and Eastern Dry Rocks off Key West are marked Yes. So the new rule governs Key Largo's reefs, and the 1997 rules still govern Key West's.

The practical result arrives on 19 January 2027. From that date the 2025 rule bans anchoring by any means in every Sanctuary Preservation Area. NOAA's preservation area page, read again on 13 October 2026, lists six exceptions: Hen and Chickens, Cheeca Rocks, Newfound Harbor Key, Eastern Dry Rocks, Rock Key and Sand Key. All three Key West areas are on it, and none of the Key Largo ones. Off Key West the 1997 wording keeps applying instead: no anchor on coral, and none when a mooring buoy is free.

One oddity follows from the split. The 2025 rule eliminated Rock Key as a preservation area, which would have reopened it to fishing, but the change does not reach state water, so NOAA still lists Rock Key SPA. No Federal Register notice announcing the rule's effective date had appeared by 13 October 2026. The full reading is in the Key Largo diving guide and the Key West diving guide.

Spiegel Grove vs Vandenberg: the big wrecks off Key Largo and Key West are both deep

Each town has one headline wreck, and both sit deeper than 130 feet at the sand. The Florida Fish and Wildlife Conservation Commission files the Spiegel Grove, a 510-foot former Navy landing ship, in 135 feet of water off Key Largo with 84 feet of relief, deployed on 17 May 2002. It files the General Hoyt S. Vandenberg, a 522-foot former missile tracking ship, in 145 feet of water off Key West with 100 feet of relief, deployed on 27 May 2009.

The difference is what sits around them. Key Largo has two more deep wrecks, the Coast Guard cutters Duane and Bibb, filed at 118 and 130 feet. It also has the shallow ones. NOAA's Shipwreck Trail puts the Benwood, a British freighter, in 25 to 45 feet between French Reef and Dixie Shoals, and the City of Washington, an iron-hulled steamship, in 25 feet on Elbow Reef. Key West's shallow trail wreck is the Amesbury, an artificial reef 5 miles west of town in less than 30 feet. The state files Joe's Tug, near the Vandenberg, at 65 feet.

NOAA studied both sinkings and found opposite results. Its summary says the Vandenberg, “unlike the Spiegel Grove, did not reduce user pressure on the surrounding natural reefs”. Off Key West, total use rose on both. For someone counting on the big wreck to empty the reef, Key Largo has the better record. Gas planning at these depths is its own topic; the nitrox explainer covers what a mix changes.

Key Largo vs Key West beaches for snorkeling: Cannon Beach or Fort Zach

The best-known beach in each town belongs to a state park, and both parks are frank about it. John Pennekamp Coral Reef State Park in Key Largo has “two human-made beaches”. Cannon Beach is its snorkeling beach, with artifacts from an early Spanish shipwreck placed about 100 feet offshore. Swimming or snorkeling outside the designated areas needs a diver-down flag. Entry is $8 per vehicle plus 50 cents a person for up to eight people, and the park is open 8 a.m. to sunset every day.

The real reef is a boat ride out. The park says three reef systems lie offshore, the closest about 300 yards out and the last more than two miles. Its concession runs snorkel boats four times a day, each 2.5 hours with about 1.5 hours on the reef, and four-hour, two-tank dive trips. One park rule surprises visiting divers: dives must be completed one hour before sunset, so there is no night diving under the park's rules.

Fort Zachary Taylor Historic State Park in Key West says it offers some of the best snorkeling from the beach in the Keys, “good for beginners”. Read the rest of the page too. Locals call it “rocky beach”, water shoes are recommended, no lifeguards are on duty, and the park sits next to the main shipping channel, whose currents it credits for the clear water. Entry is $6 per vehicle. Without a boat, Fort Zach is the easier way to fish from the shore; in Key Largo the reef starts with a boat ride.

The Dry Tortugas are a Key West day trip, but your scuba tanks stay behind

Dry Tortugas National Park lies about 70 miles west of Key West, with no road. This is the one thing Key West can sell that Key Largo cannot. The park's authorized ferry, the Yankee Freedom, leaves from 100 Grinnell Street at 08:00, reaches Fort Jefferson at 10:15, leaves again at 15:00 and docks in Key West around 17:15. Snorkel gear and the $15 park entrance fee are included in the ticket.

Scuba is another matter. The park states that the ferry and seaplane “are unable to carry compressed canisters aboard”, and the ferry lists compressed gas among the things not to bring. To dive the Tortugas you need your own boat or a charter vessel. A private boat whose occupants dive, snorkel or use the park's mooring buoys also needs a permit from the superintendent under 36 CFR 7.27(h), which the rule allows to be given by radio or telephone.

From Key Largo, the ferry's 07:00 check-in means a night in Key West first. For a snorkeler, though, the ferry day alone may decide this comparison.

Spearfishing: banned around Key Largo by two rules that stop short of Key West

For spearfishers the Key Largo vs Key West question has a short answer. Florida Statutes section 379.2425 prohibits spearfishing in Pennekamp and in the Upper Keys, defined as all salt water under the state wildlife commission's jurisdiction from the Miami-Dade line south “down to and including Long Key”. Beyond the state line, the sanctuary bans “fishing with, carrying or possessing” spearguns, pole spears and Hawaiian slings in the Key Largo Management Area. The same federal ban covers the small Looe Key Management Area.

Key West's reefs sit outside both lines. Spearfishing there follows the state's general rules and the sanctuary's zones: the preservation areas at Sand Key, Rock Key and Eastern Dry Rocks, and the Western Sambo Ecological Reserve, are no-take for everyone. West of Sand Key, Florida closes Western Dry Rocks to fishing and to possessing fish from 1 April to 31 July, and its stowage clause covers spear gear. Diving there is not restricted.

Key Largo vs Key West water temperature, and the hurricane months they share

NOAA's National Data Buoy Center ran weather stations on the reef at both ends: Molasses Reef off Key Largo and Sand Key off Key West. Its climatic summaries give the monthly mean sea temperature for each.

In the Key Largo vs Key West water comparison, the gap is a winter one. From December to February the water at Molasses averaged 0.4 to 0.8°C warmer than at Sand Key; from June to October the two are within 0.2°C. Treat these as long-run averages, not this year's water. The Molasses figures cover December 1987 to December 2008 and the Sand Key figures May 1991 to September 2005, and neither station has reported a water temperature to the data center since early 2019. The 2023 summer ran far above them: NOAA's sanctuary recorded warm water from February that year and called it the longest-lasting marine heat wave in the region since 1991.

Storm season does not split. The National Hurricane Center gives the Atlantic season as 1 June to 30 November, with a peak on 10 September and most activity from mid-August to mid-October. Both towns sit on the same chain of islands, on the same road out. For a stay of weeks in that window, book something you can leave on short notice.

Coral after 2023: Key Largo's outer reefs ran cooler, Key West kept its elkhorn

A study published in December 2024 called the summer 2023 heat wave “the most severe on record for Florida's Coral Reef”. It tracked brain and boulder corals at nine reefs from Sand Key to Carysfort. At seven of the nine, only 0 to 2% of the tracked colonies suffered any mortality, and both towns' outer reefs were in that group. The two badly hit sites were inshore, Newfound Harbor and Cheeca Rocks, with 43% and 30% of monitored corals dead. On temperature, the authors found Grecian/Key Largo Dry Rocks and Carysfort “consistently the coolest” of their sites.

The branching corals tell a different story. Seven reefs are NOAA's Mission: Iconic Reefs restoration sites, among them Carysfort and Horseshoe off Key Largo and Eastern Dry Rocks off Key West. After the heat, a NOAA survey found less than 22% of about 1,500 outplanted staghorn corals alive, and only at Carysfort and Horseshoe. Live elkhorn turned up at three sites, Carysfort, Sombrero and Eastern Dry Rocks. Expect restoration work on both sides, not untouched reef.

The Florida Keys hyperbaric chamber is near Key Largo, a long way from Key West

Baptist Health says Mariners Hospital, at 91500 Overseas Highway in Tavernier, is “home to the only hospital-based hyperbaric chamber in the Florida Keys”, used for diving injuries. The hospital runs a 24-hour emergency department with an on-site helipad. Tavernier sits at the southern end of Key Largo, so a Key Largo diver is close to it.

For Key West that chamber is at the far end of US 1. Lower Keys Medical Center in Key West offers 24-hour emergency care, and its services list does not include hyperbaric medicine. The route from any boat is the same: Divers Alert Network tells divers to call 911 first in a life-threatening emergency, then its emergency line on +1-919-684-9111. Check that your dive insurance pays for an air transfer as well as the treatment.

The road itself is long. Florida State Parks puts the Overseas Heritage Trail corridor from Key Largo to Key West at 106 miles, and the state's scenic highway program gives the Keys byway on US 1 as 110 miles from Key Largo. Key West has its own airport, Key West International; Key Largo is the end of the chain nearest Miami.

Key Largo and Key West dive shops on our lists

Both lists are small, and each reaches well beyond the town in its name.

SSI files four of the Key Largo entries in Key Largo itself, one in Tavernier and one in Islamorada. Of the Key West five, only two are filed in Key West; the others sit in Big Pine Key, Ramrod Key and Summerland, closer to Looe Key than to Sand Key. The Key Largo operator list and the Key West operator list name them. These are membership registers, not licenses, and a Green Fins digital membership is a self-evaluation rather than an in-person assessment of the shop.

Key Largo for reef mornings, Key West for the Tortugas and its own airport

Base in Key Largo if you want to dive often on reefs a short ride out, if you want shallow wrecks alongside the Spiegel Grove, or if a chamber within reach matters to you, as it should on a month of deep wreck dives. Winter water runs a little warmer there. Do not come to spearfish.

Base in Key West if the Dry Tortugas are on your list, if you spearfish, or if you want an airport on the island. At Sand Key, boats may still anchor after January 2027 under the 1997 rules, though not on coral and not when a buoy is free. For a long stay, Key Largo vs Key West need not be either/or: a month at each end, with Looe Key in between, covers the reef line. The Miami diving guide covers the stretch north of Key Largo.

Note: Sanctuary rules in the Keys are in flux, and the 2027 anchoring date may still move. Check the zone you plan to dive with NOAA and your boat, and follow the briefing on board.