Keys Active Road Trip: Reef, Flats & Bahia Honda's Best Beach

The first undersea park in America, established in 1963, protects 70 nautical square miles of the Florida Reef — the third-largest barrier reef system in the world. The 9am snorkel trip to Molasses Reef passes through some of the healthiest coral in Florida: elkhorn and staghorn formations rising from the sandy bottom, parrotfish grazing the coral, sea turtles resting on the ledges, nurse sharks cruising the deeper cuts. The reef rises to within 10 feet of the surface at its peaks. Book in advance — this is the most popular Keys activity and sells out every weekend.

Use the afternoon to explore a different trail, cool off at a swimming hole, or find a scenic spot to watch the sunset.

For $3 admission and $4 for a bucket of baitfish, visitors to Robbie's Marina can hand-feed Atlantic tarpon from a low wooden dock over Florida Bay — and these are not small fish. The tarpon that gather here year-round weigh between 50 and 200 pounds, and they compete for baitfish with the aggression of creatures that have been doing this for 80 million years. Tarpon — which can grow to 8 feet and 280 pounds — are one of the premier saltwater sport fish in the world and one of the most prehistoric: their species is virtually unchanged since the Jurassic period. Feeding them from the dock at Robbie's is chaotic, splashy, and surprisingly involving. Pelicans also compete for the baitfish from above. One of the best $7 experiences in Florida.

The Florida Bay backcountry north of Islamorada is an archipelago of mangrove islands, tidal creeks, and grass flats that extends 30 miles toward the Everglades — one of the largest estuarine wilderness areas in the United States. Kayaking the backcountry from a launch at Robbie's or Anne's Beach reveals a world utterly different from the Atlantic side: shallow, warm, gin-clear water above seagrass beds, bonefish tailing in the shallows, osprey diving ahead of your bow, loggerhead sea turtles surfacing to breathe in the tidal channels. The wind is the primary challenge; morning paddling is always calmer than afternoon in the Keys.

Bahia Honda ('deep bay' in Spanish) State Park is consistently rated as having the finest beach in the Florida Keys — and possibly the finest in all of Florida — with Sandspur Beach offering extraordinarily fine white sand, clear turquoise water that transitions from sand-bottom shallows to grass flats, and the dramatic backdrop of the old Flagler Railroad Bridge overhead. Henry Flagler's original Overseas Railroad crossed here on what was, at the time of its 1912 opening, an engineering marvel: the Bahia Honda Bridge required special construction techniques because the channel here is the deepest between Miami and Key West, the water rushing through in powerful tidal currents. When the Florida East Coast Railway was upgraded for automobile use after the 1935 hurricane destroyed the railroad, the Bahia Honda span could not be widened — so the road was built on top of the old railway truss, one of the most improbable bridge adaptations in American highway history. The old bridge is still standing and partially open for walking — the views from its elevated deck across the Atlantic and Florida Bay simultaneously are spectacular.

The park has picnic facilities (bring your own food). Alternatively, Herbie's Bar & Chowder House in Marathon (10 min north) is the Keys classic for a midday fish sandwich and cold beer. Either way, eat before the Seven Mile Bridge walk.

Use the afternoon to explore a different trail, cool off at a swimming hole, or find a scenic spot to watch the sunset.

The old Seven Mile Bridge — replaced in 1982 by the current US-1 bridge — is now closed to vehicles and open for walking and cycling, extending 4.7 miles from Marathon over open Atlantic water before ending mid-ocean above a reef. Walking it at any distance offers total immersion in the experience Flagler's engineers and workers faced: open ocean on both sides, the wind and swells and the vast emptiness of Florida Bay to the north and the Atlantic Reef tract to the south. The abandoned roadway ends at Pigeon Key, the historic 1908 construction worker camp. The view from the bridge at sunset, looking west over Florida Bay, is one of the great Florida vistas.