Sailing the Florida Keys

Cruising Guide · Florida & Southeast

The Florida Keys are a chain of limestone islands trailing southwest from the mainland for 125 miles, terminating at Key West 90 miles from Cuba. They sit between two bodies of water with almost nothing in common: the Atlantic Ocean to the south and east, with its clear offshore depths and world-class reef system, and Florida Bay to the north and west, a vast, shallow, hard-to-read expanse that drains into the Gulf of Mexico. Which side you sail on determines everything about what kind of sailing you get.

The Keys are also a cruiser destination in a specific sense — not a place most people sail past, but a place where boats stop for weeks or months. Boot Key Harbor in Marathon is one of the most concentrated cruiser communities in North America. Key West is a destination in its own right, and the most common staging point for the Bahamas crossing. November through April, the anchorages fill with boats that have come down the Atlantic Intracoastal Waterway from the northeast, or offshore from the Carolinas, and are either wintering in place or planning to go somewhere warmer.

The Inside Route vs. the Outside

The Intracoastal Waterway runs through the Keys via Florida Bay — "the inside." The depths in Florida Bay are notoriously thin; much of it is 4–6 feet at mean low water, and the charted depths in the bay are known to shift. Boats drawing more than 4.5 feet approach the inside route with real caution, and boats drawing over 5 feet often choose not to attempt it at all. Groundings in Florida Bay are a chronic occurrence among boats transitioning from the ICW to the Keys; the Bay has soft mud bottoms, which means groundings are survivable, but the current charts require verification against recent cruiser reports.

The outside — the Atlantic side — runs in open water with depths exceeding 100 feet once clear of the reef line. The Florida Reef Tract is the third-largest coral barrier reef in the world, running roughly parallel to the Keys at distances from 4 to 7 miles offshore. It is marked with lights and the channels through it are well-charted, but the reef does not forgive careless navigation. The shoaling on the reef is sudden — you can go from 30 feet to 3 feet in a boat length if you stray off a charted passage. Running the outside requires attention to chart, GPS, and the water color, which changes from deep blue to pale green as the bottom comes up.

Most offshore passages along the Keys are made on the Atlantic side, transitioning to inside routes for anchorage access. The Hawk Channel, between the Keys and the reef, provides a protected corridor in 12–20 feet of water for the length of the chain.

Key Largo

The first stop coming south from Miami, Key Largo is more gateway than destination — long and thin, with anchorage options at Rodriguez Key (a popular overnight stop in the shelter of the cay, 9–10 feet, good holding) and marina facilities along the Florida Bay side. John Pennekamp Coral Reef State Park makes Key Largo a snorkeling and diving base; for sailors, the more relevant feature is the mooring field off the park, which provides access to the reef system without anchoring on coral.

Islamorada

The Upper Keys town of Islamorada is a sport-fishing center with provisioning, fuel at Bud N' Mary's marina, and anchorage in Whale Harbor Basin. The Islamorada area has more fish (and more fishing boats) than sailing infrastructure, but it is a practical stop for provisions and fuel for boats making the Keys transit.

Boot Key Harbor, Marathon

Boot Key Harbor is unlike any other anchorage in the Keys and arguably unlike any anchorage in North America in terms of the social density and culture it supports. The City of Marathon operates a large mooring field in the harbor — 190-plus moorings — at reasonable daily and monthly rates, and the anchorage surrounding the mooring field adds additional capacity. In winter the harbor regularly holds 300 or more boats.

What makes Boot Key distinctive is not the mooring field but the community infrastructure around it. The Cruiser's Net broadcasts on VHF Ch 68 at 9 am daily: weather forecast, announcements, "what's available and what's needed," and the organized activities of a self-governing community of people who have converged from every point on the compass. Dinghies go back and forth to the Marathon dinghy dock all day. There are happy hours, potlucks, weather briefings for Bahamas crossings, and an informal network of expertise — riggers, diesel mechanics, sailmakers, electricians — that operates largely by word of mouth.

The City Marina dinghy dock is the social center. The Dockmaster's office handles check-in and monitors the VHF net. Provisioning in Marathon is adequate if not exceptional; the Publix on US 1 is the standard grocery run. Marathon is where boats that need work get it done, where Bahamas-bound crews get their paperwork in order, and where the decision gets made about whether this winter turns into a Bahamas year or not.

Key West

Key West is the end of the road in multiple senses. It is the southernmost point in the continental United States, 90 miles from Cuba, and the last significant provisioning and repair stop before the Bahamas or beyond. The anchorage off Christmas Tree Island and in the Bight of Key West is popular and often crowded; the Key West Bight Marina, City Marina, and Garrison Bight Marina all have guest slips. Fuel is available at multiple locations.

Key West itself is loud, colorful, and not particularly oriented toward serious sailing. The Duval Street scene is its own thing. For cruisers, the town is a provisioning stop and a weather-window-watching station. Bahamas-bound boats check in at the West Marine, check out at Customs, and wait for the right Gulf Stream crossing window.

Weather Windows for the Bahamas Crossing

The crossing from Key West or Lake Worth (Palm Beach) to the Bahamas requires crossing the Gulf Stream, a 25-50 mile stretch of north-flowing current running at 2–5 knots. The crossing is benign in light conditions and genuinely dangerous when a north wind blows against the northward-flowing current — the sea state produced by 20 knots of wind against the Gulf Stream is steep, short-period, and physically punishing.

The standard protocol: wait for a south or southeast wind of 10–15 knots with a stable forecast for 24 hours. A high-pressure system moving through from the northwest will produce the window — southeast winds on the back edge of the high. The crossing from Lake Worth to West End, Grand Bahama is 55 miles; from Key West to Lucaya is about the same. Good weather windows come every 10–14 days in winter. Impatient or poorly-timed crossings are the single most common cause of serious incidents on the Florida-Bahamas passage.

Hurricane Season and Where Boats Go

June 1 through November 30 is the official Atlantic hurricane season; the Keys are directly in the Atlantic hurricane corridor. Boats that winter in the Keys face a decision each May: stay and ride it out in a marina (genuinely risky in a direct hit), haul out and leave the boat (expensive and labor-intensive), or move the boat north or west out of the primary track area.

The most common strategy is to move the boat north — to a hurricane hole on the Florida west coast, up the ICW to the Carolinas, or to a well-protected inland marina in central Florida. Stuart, on the east coast, has a number of marinas that market specifically to hurricane haul-out customers. Boats that remain in the Keys during active hurricane season are typically on long-term leases at commercial facilities with hurricane tie-down infrastructure — not anchored or on moorings, which are not survivable in a direct strike.

Reef Navigation: Water Color and Polarized Glasses

Navigating near the Florida Reef — and later, around Bahamian coral heads — requires abandoning the habit of trusting the chartplotter completely. The reef charts are accurate in broad strokes, but patch reefs, bommies, and coral heads do not all make it onto nautical charts. Water color is the real-time depth gauge: deep blue is safe; turquoise means the bottom is coming up; pale green or white means shallow and possibly coral. Polarized sunglasses are essential — they cut the surface glare that makes the water color unreadable. Position someone on the bow, have them call back what they see, and drive from there in unfamiliar shoal areas. This is how it is done in the Bahamas and it is how it is done in the reef passages of the Keys.

← All Cruising Guides  |  Florida Marinas →

Frequently Asked Questions

What is the difference between the inside route and outside route through the Florida Keys? The inside route through Florida Bay and the backcountry between the Keys and the mainland is a shallow-water passage averaging 5–7 feet of depth, with numerous shoals requiring careful navigation by depth sounder and chart — it is accessible to shoal-draft boats but requires attention and cannot be sailed in the dark safely. The outside route runs along the Atlantic side of the Keys in the Florida Straits, in deep water with Gulf Stream effects and the sea exposure of the open Atlantic. Most cruising boats use both routes depending on conditions and destination — the inside route for exploring the backcountry and fishing, the outside route for passage-making.

What is Boot Key Harbor and why is it the center of cruising life in the Middle Keys? Boot Key Harbor in Marathon is a large, well-protected harbor with a city-operated mooring field offering the lowest-cost long-term mooring in the Florida Keys — monthly rates are typically $300–$500 per month, including launch service, access to the cruiser's lounge, showers, and laundry. The harbor's active cruising community, with regular potlucks, a VHF cruiser's net, and an established network of local knowledge, has made it the gathering point for sailors making or planning Bahamas crossings. The combination of low cost, good facilities, and a large community of experienced offshore sailors is unique in South Florida.

What is the optimal timing for a Bahamas crossing departure from the Florida Keys? The optimal Bahamas crossing window from the Keys differs from the Fort Lauderdale crossing in distance — crossing from Marathon or Key West to the Bahamas is 80–100 miles to Bimini or Nassau, compared to 56 miles from Fort Lauderdale to West End. The increased distance means the crossing takes 12–16 hours at typical cruising speeds, requiring either a late-night departure for daylight arrival or an early departure accepting an evening arrival before darkness. The weather window requirement is identical to the Fort Lauderdale crossing: a settled high with no northerly wind forecast for 24 hours, verified the morning of departure.

What are the navigation hazards specific to the Florida Keys approach from the north? The approach from the north to the Keys via Florida Bay has some of the most shoal-strewn waters in the US coastal system — numerous banks, flats, and bars with controlling depths of 3–5 feet extending across the bay. The Florida Bay route requires a chartplotter with current electronic charts matched to GPS, a detailed Florida Keys cruising guide with waypoints, and slow-speed piloting by depth sounder for any unfamiliar sections. The Intracoastal Waterway through Florida Bay is marked but the markers do not reveal all hazards, and grounding on a soft mud flat is the most common Keys cruising incident.

What facilities and provisioning are available in Key West for offshore departures? Key West has excellent offshore departure facilities — Conch Harbor Marina and Stock Island Marina Village both serve as departure-prep marinas with fuel, water, and provisioning access. The city's proximity to the Northwest Passage to the Gulf of Mexico and the Bahamas crossing routes makes it a natural staging port. Provisioning in Key West is adequate but more expensive than mainland Florida — Publix is the primary grocery resource, and serious offshore provisioning is typically done in Fort Lauderdale or Miami before heading south. The chandlery resources in Key West are modest; parts and equipment should be obtained before reaching the Keys.