St Thomas or Vieques?

Both islands are built around their beaches, with equally warm, clear water. The real difference is how much comfort you get. St Thomas has the classic setups: the sheltered horseshoe of Magens Bay, the Sapphire and Secret Harbour coves near Red Hook where you can stay within walking distance of the sand, and snorkelling off Coki Point. St John's north shore is only twenty minutes away by ferry. The catch is that cruise days fill the famous beaches.

Vieques offers emptiness instead. Sun Bay and Media Luna are calm and close to Esperanza, and refuge beaches such as Caracas and La Chiva have reefs near the shore and hardly anyone on them. In return you bring your own water and shade, drive some dirt tracks and swim without lifeguards.

Neither island is a reason to travel for food, and the two are roughly level, but the cooking differs. St Thomas serves West Indian food, such as johnnycakes, saltfish pates, kallaloo and fungi with boiled fish. Frenchtown and Red Hook also have a handful of sit-down restaurants with sea views.

Vieques eats Puerto Rican: mofongo and fish tacos along Esperanza's seafront, and alcapurrias from roadside kiosks. Kitchens there keep short hours and often close out of season, so self-caterers should stock up before the ferry.

St Thomas has more history to see, all of it in Charlotte Amalie. The capital has two centuries of Danish rule behind it, with stone warehouses along alleys down to the harbour, the 99 Steps, Fort Christian and a synagogue with a sand floor that is among the oldest in the Americas. That fills a half day to a full day.

On Vieques, an afternoon is enough. The small Fortín Conde de Mirasol tells the island's story, and the naval bombing-range years are the most striking part of it. Lighthouses, sugar ruins and an ancient ceiba tree make up the rest.

Neither island has clubs, but St Thomas at least has a proper evening out. The open-air bars around the Red Hook ferry dock bring boat crews, residents and visitors together late into weekend nights, and Frenchtown adds a few waterside bars.

On Vieques, evenings mean a drink or two along Esperanza's seafront strip and an early night. For many visitors, the night out is a kayak trip on the bioluminescent bay.

The outdoors is equally good on both, but in different ways. St Thomas works as a gateway. Its own trails are few, but St John's national park is a short ferry ride away, with forest paths to petroglyphs and sugar mill ruins and an underwater trail off Trunk Bay. Red Hook is also a starting point for sailing east through the sheltered channels of the Virgin Islands.

Vieques has the more unusual sight on its own shore: Mosquito Bay, where the water glows blue-green on dark nights, so time your visit away from the full moon. By day there is the refuge's dry forest and salt ponds for cycling and birdwatching, with semi-wild horses beside the roads.

St Thomas is the better base for island-hopping. Ferries run often to Cruz Bay on St John and across to Water Island. The British Virgin Islands, from Jost Van Dyke's beach bars to the boulders of Virgin Gorda, are close enough for a day if you bring a passport, and St Croix's Danish towns make a longer outing.

From Vieques, the one good outing is Culebra and Flamenco Beach, and that means a chartered boat. Old San Juan is a long day by ferry and road, so most visitors stay on the island.

St Thomas is the easier island with children. Coral World next to Coki Point has touch pools and turtles, older children can snorkel off the beach, the Skyride makes a short outing, and the resorts are set up for families. Steep roads and the midday heat still make day trips more tiring than the island's size suggests.

Vieques suits families who are happy with sand, snorkelling and horses on the road. Media Luna's shallow water is ideal for small children, and older ones remember the glowing bay for years. There are no lifeguards or children's attractions, though, and serious medical care is on the main island.

Getting around takes effort on both islands, but St Thomas is the simpler of the two. Safari taxis run fixed routes, hire cars are easy to find, and ferries from Red Hook to St John leave often. The difficulties are driving on the left on steep, winding roads and heavy traffic around the capital on cruise days.

On Vieques, the hard part starts before you arrive. Ferries from Ceiba often sell out, so many people take a small plane instead. Once there, you need a jeep for the dirt tracks into the refuge, and there are few enough that you should book well ahead.

This is the widest gap between the two islands. St Thomas has a proper shopping district: the duty-free stretch of Main Street and its old stone warehouses, repeated at Havensight by the cruise dock, is aimed at visitors buying jewellery, watches, perfume and rum. It suits a specific purchase better than a browse.

On Vieques, shopping is limited to a few galleries and craft stalls in Esperanza and Isabel Segunda and a grocery store with a small range.

Both are expensive, but Vieques costs somewhat less. Simple guesthouses in Esperanza, a kitchen to cook in and the ferry instead of a flight all keep the bill down, although jeep hire is a cost you cannot avoid.

St Thomas charges top Caribbean rates for rooms in the winter high season, and taxis charge each passenger separately, which adds up quickly for a family. Its local lunch counters and roadside stands are the cheapest way to eat.

Neither island has much of a stage, but St Thomas has more. The open-air Reichhold Center hosts occasional concerts and touring acts. Carnival in spring brings steel pan, quelbe folk music and mocko jumbie stilt-walkers onto the streets for several weeks.

On Vieques, the most you can expect is a guitarist in an Esperanza bar or the yearly patron saint festivities in Isabel Segunda, with bomba and plena in the town square. For anything more, you go to San Juan.

Neither island has a bathing tradition, and both are restful because of their pace rather than their treatments. On St Thomas, that means a resort spa with a sea view and a base on the east end or north shore, away from the harbour on busy cruise days.

Vieques is quieter all round, with no high-rise hotels, little traffic and roosters instead of nightlife. Its wellness offer is a few yoga classes and massages at guesthouses rather than a proper spa.