Marco Island or Myrtle Beach?

Both have long, flat, pale-sand beaches with small waves, so the differences lie in the water and the season. Marco Island's single crescent faces the calm, shallow Gulf. It has the Tigertail lagoon and sandbar for wading and shelling, Keewaydin Island's undeveloped shore is a short boat ride away, and the sun sets over the water. The sea stays swimmable for most of the year, though some find it bracing in the winter months.

Myrtle Beach simply has far more sand. The Grand Strand runs from the crowded, tower-lined central blocks to quieter, dune-backed stretches at Surfside and Garden City. The Atlantic there is greenish rather than clear, and it is only warm enough for swimming from late spring to early autumn.

Neither is a food destination. Both rely on seafood and offer a narrow range beyond it. Marco Island's version is calmer and pricier: grouper, shrimp and winter stone crab at waterfront grills and resort dining rooms. Goodland's dockside fish platters are the looser option, and Naples, half an hour away, is the place for a serious dinner.

Myrtle Beach feeds crowds instead, with seafood buffets, pancake houses and chains along the strip. Its better meals are at Murrells Inlet, where the catch comes in on local boats, and in the lightly battered Calabash style just over the North Carolina line.

Neither has much to see, but Myrtle Beach has a little more. Brookgreen Gardens is a former rice plantation filled with American sculpture under live oaks, with exhibits on the people enslaved there, and it makes a worthwhile morning. The Moorish-style Atalaya stands next door.

Marco Island's one real stop is its historical museum, which tells the story of the Calusa and of the carved wooden figures found on the island. For museums and galleries beyond that, you need to go to Naples.

In summer, Myrtle Beach has a real if unpolished night out. There are beach bars and rooftop decks around the boardwalk, dance clubs in the entertainment complexes that stay open late, and the shag, the Carolina beach dance, still danced in the old clubs of North Myrtle Beach. Spring break and rally weeks can get rowdy.

Marco Island has nothing of the kind. An evening there means sunset drinks on a waterfront deck, dinner and perhaps a resort lounge. Goodland's dockside bars are lively on winter weekend afternoons, not at night.

Marco Island is the place for wildlife. It sits on the edge of the Ten Thousand Islands, so paddling through mangrove channels, watching dolphins and manatees and fishing for snook and tarpon are everyday activities. Everglades National Park, Big Cypress and the Fakahatchee Strand are all within an hour.

Myrtle Beach offers smaller, gentler pleasures: maritime forest in the state park, marsh boardwalks with herons and alligators at Huntington Beach, and kayaking on the blackwater Waccamaw River. Its main outdoor draw is golf. Both are flat, with no real hiking.

Myrtle Beach has the stronger outing in Charleston, about two hours away, with its antebellum streets, harbour forts and plantations. Closer options include historic Georgetown, Pawleys Island and Wilmington's riverfront. Marco Island's list is shorter and leans towards nature rather than towns: Naples, Everglades City and the trading post at Chokoloskee, and the Edison and Ford Winter Estates at Fort Myers.

Myrtle Beach has been built around children for generations. It has an aquarium, an amusement park with a wooden roller coaster, water parks, the observation wheel on the boardwalk and pirate-themed mini-golf, and resort hotels have lazy rivers and suites with kitchens. Spring break weeks and some late-night oceanfront blocks are best avoided.

Marco Island suits younger children in a quieter way, with calm shallow water, wading at Tigertail, shelling, dolphin boat trips and resort pools with children's programmes. For a zoo or a children's museum, you have to drive to Naples.

Both need a car, so the difference is one of scale. Marco Island is small and flat, and its cycle paths make it easy to ride between the beach, shops and restaurants in the cooler months.

Myrtle Beach sprawls along busy multi-lane highways with few pavements, and summer traffic on Kings Highway is slow. Walking only works within a single resort area or along the sand itself.

Myrtle Beach has more to buy on the spot: two large outlet centres, waterfront shopping complexes, The Market Common on the old air base and enormous beachwear shops. It has no luxury streets, though, and few independent boutiques.

Marco Island itself has only small plazas selling resort wear and shell souvenirs. Its better shopping is in Naples, where Fifth Avenue South and Third Street South offer the kind of upmarket boutiques that Myrtle Beach lacks.

Myrtle Beach is by far the cheaper stay. Its sheer number of motels, condos and oceanfront rooms keeps rates low outside July and long weekends, and units with kitchens cut food costs.

Marco Island is expensive throughout, most of all from January to April, when restaurants are priced for a wealthy winter crowd. Rates fall in summer, but the island never becomes a bargain. In both places, a hire car adds to the bill.

Marco Island leans towards the classical, though at one remove. On the island there is a small community theatre and musicians in the resort bars in winter, but the real programme is in Naples, where the philharmonic orchestra and touring shows play mostly during the winter season.

Myrtle Beach keeps its entertainment on the spot and aims it at families: country, gospel and comedy revues, Christmas shows, dinner theatre with knights and pirates, and touring country and rock acts at the main entertainment complex. It is polished, but there is no orchestra or serious drama.

Marco Island is the more restful of the two. The whole island moves at an unhurried pace, its beachfront resorts have full spas with pools overlooking the Gulf, and there are yoga classes and day spas in the plazas.

Myrtle Beach has spas in its oceanfront and golf resorts, but the summer strip is loud and car-bound. Rest there means heading to Pawleys Island or coming in spring or autumn. Neither place has a bathing tradition.