Islamorada or Siesta Key?

This is Siesta Key's home ground. Siesta Beach is wide, white and soft, shelving into calm Gulf water, with quieter Crescent Beach for snorkelling round Point of Rocks and Turtle Beach for shells and shark teeth. You can spend a whole week on the sand without getting in a car.

Islamorada offers warm, shallow water but little beach: Anne's Beach and the small highway parks are thin strips where you wade a long way before it deepens. Its best swim is by boat at the Whale Harbor sandbar, and for real sand you drive an hour to Bahia Honda.

Neither place is a food destination, and both lean on seafood eaten on an open-air deck. Islamorada's edge is freshness: same-day snapper, hogfish and mahi-mahi, and kitchens that will cook your own charter catch, though a week can feel like a lot of fried fish.

Siesta Key's own cooking is beach fare, grouper sandwiches and shrimp baskets around the village, but Sarasota twenty minutes away widens the choice with international restaurants downtown and around St Armands Circle, plus a Saturday farmers' market.

Siesta Key has nothing to visit on the island itself, but Sarasota's Ringling estate gives it a real advantage: Baroque painting including large Rubens canvases, the Venetian Gothic Ca' d'Zan and the circus museum, with the Selby gardens and mid-century modern houses besides.

Islamorada's sights are small and local, the History of Diving Museum, the memorial to the 1935 Labor Day hurricane, and the wrecking-settlement ruins on Indian Key reached by kayak. They fill a half day with good stories rather than a full cultural itinerary.

Siesta Key has more going on after dark, though modestly. Siesta Village packs a few blocks of open-air bars with cover bands and frozen cocktails, crowded with students at spring break, and downtown Sarasota adds rooftops and cocktail bars for a more grown-up evening.

Islamorada's night is essentially sunset at a tiki bar or dockside deck, noisier with boaters at weekends, then early bed before a dawn start on the water. Neither has clubs.

Islamorada has the richer natural offer, almost all of it on the water. Florida Bay's flats are famous for bonefish, tarpon and permit, the Gulf Stream brings sailfish and tuna, Alligator Reef gives clear-water diving, and boats run into the Everglades backcountry. Dry land is scarce, so walking is limited to the cycle path and short trails.

Siesta Key's nature is gentler: dolphins seen from the beach, manatees in winter, nesting turtles in summer and kayaking through the mangrove tunnels of Lido Key. Its best land outing, Myakka River State Park with alligators and a canopy walkway, gives it the trails Islamorada lacks.

The range is similar, but the geography is not. From Islamorada everything lies on one road: Key West two hours south over the Seven Mile Bridge, with the Turtle Hospital in Marathon on the way, or Key Largo and Miami to the north, so one long outing in each direction is the realistic plan.

Siesta Key sits on a coast that opens both ways, with St Petersburg's Dalí Museum, Tampa's Ybor City and the Tarpon Springs sponge docks north, and Venice and Boca Grande south, giving more choice at shorter distances.

Siesta Key is the easier place with young children. The main beach shelves so gradually that toddlers can paddle far out, and it has lifeguards, a playground and showers, while condo rentals with kitchens and pools make long stays simple. Mote Marine Aquarium on Lido Key is the main rainy-day outing.

Islamorada works better for older children who enjoy boats: hand-feeding tarpon at the docks, Theater of the Sea's dolphin shows and reef snorkelling at Pennekamp. With small beaches and a charter-driven rhythm, toddlers have less to do.

Both rely on the car for anything beyond the immediate surroundings, but the day-to-day feel differs. Islamorada is strung out for about 30km along the single Overseas Highway, so even dinner usually means driving, with the Heritage Trail for cyclists and boats for much of the rest.

Siesta Key is compact at about 13km, with a walkable village and a free trolley running the length of the island, so a pure beach stay can go car-free. The catch comes when crossing to Sarasota, as the bridges and beach car parks fill in high season.

Siesta Key is the better bet, mainly thanks to its neighbours. Beyond the island's swimwear and gift shops, St Armands Circle has upscale boutiques and jewellers, and Sarasota's Main Street adds bookshops and galleries.

Islamorada's most interesting shopping is a large, long-established outfitter for tackle and outdoor gear, plus marine-art galleries and a roadside craft village. For anything fashionable it means a trip to Miami.

Neither is cheap, but Siesta Key is the easier one to keep in check. The beach and trolley cost nothing, and a rented condo with a kitchen cuts down on restaurant bills, even though high-season rentals are pricey.

Islamorada costs more because the trip itself is expensive: fishing charters, boat rentals and dive trips are the reason to come, and they add up quickly on top of waterfront lodging. In both, summer is the cheaper but hotter, stormier season.

The gap is wide. Sarasota gives Siesta Key a real stage life: a resident opera in a restored 1920s opera house, the Asolo Repertory Theatre at the Ringling, a ballet company, a symphony and touring shows at the lavender Van Wezel hall, best from autumn to spring. On the island there are bar bands and the Sunday sunset drum circle.

Islamorada offers little beyond a guitarist playing covers at sunset and the odd community concert, and a proper show means driving to Miami or Key West.

Both are places to slow down rather than to take the waters, and neither has a bathing tradition. In Islamorada the calm comes from early starts on the water, with spa treatments in open-air cabanas at a few waterfront resorts and yoga on the docks at sunrise.

Siesta Key's version is the beach itself, with morning walks and quiet afternoons at the south end near Crescent and Turtle beaches, backed by small day spas, beach yoga and condo pools.