British Virgin Islands or Saint-Martin?

Both are first-rate beach destinations with warm, clear water all year, and the difference lies in how you reach the sand. In the British Virgin Islands many of the best beaches, White Bay on Jost Van Dyke or the reef-fringed shores of Anegada, are reached by boat, and The Baths on Virgin Gorda add granite grottoes found nowhere on Saint-Martin.

Saint-Martin's beaches are mostly a drive away. Orient Bay is the long, sociable one with sunbeds and water sports, the west coast bays are quieter for snorkelling off the sand, and Le Galion is the gentlest for paddling. Its east-facing bays sometimes collect seaweed, while the BVI's north shores take winter swell.

Saint-Martin eats much better. Grand Case alone, with French and creole restaurants over the water next to lolo barbecue stalls, outdoes anything in the British Virgin Islands, and proper bakeries and French cheese and wine raise the everyday standard too.

The BVI's pleasures are simpler: rotis and conch fritters in Road Town, lobster grilled on the beach at Anegada and a painkiller at a Jost Van Dyke bar. Outside Road Town and the resort dining rooms the choice runs thin quickly.

Neither island is a place for sightseeing, and each has about a morning's worth. In the British Virgin Islands that means the Old Government House Museum in Road Town, a working rum distillery at Cane Garden Bay and the Cornish engine house of the Copper Mine on Virgin Gorda. On Saint-Martin it is Fort Louis above Marigot, the town's painted creole houses and a small museum of Arawak and salt-pan history.

Evenings are low-key on both, but they take different forms. In the British Virgin Islands, nights follow the sailing crowd from anchorage to beach bar on Jost Van Dyke and Norman Island, with full-moon parties at Trellis Bay as the set piece. Most people turn in early, and there are no clubs.

Saint-Martin's French side centres on long dinners and terraces in Grand Case. The difference is that real late nights are available, in the clubs and casinos at Simpson Bay and Maho just over the border.

The British Virgin Islands have the richer outdoors, nearly all of it at sea. Dozens of islands sit close together around a sheltered channel with steady winds, and the Rhone wreck and the reef around Anegada are proper dive and snorkel sites. On land there are short forest trails on Sage Mountain and flamingos on Anegada's salt ponds.

Saint-Martin has a greener, hillier interior, with trails up Pic Paradis and a treetop park, and its nature reserve around Tintamarre has turtles and rays. It makes for pleasant active days rather than the reason for the trip.

Saint-Martin is the better base for days away. Anguilla's long, quiet beaches are a short ferry from Marigot, St Barths offers Gustavia's polished harbour, and Saba and Sint Eustatius make a longer day. On the island itself, Philipsburg is an easy half-day.

From the British Virgin Islands, ferries mostly lead to small places such as Spanish Town or Great Harbour. The one substantial outing, Charlotte Amalie on St Thomas, means crossing into the US Virgin Islands with a passport.

Both work for families who love the water and lack anything built for children. The British Virgin Islands give older children the adventure of a charter boat, but boat transfers and steep roads take more managing with toddlers. On Saint-Martin, villas with kitchens and pools, the shallow bay at Le Galion and small extras such as the zipline park and the low planes at Maho make life slightly easier with little ones.

Both need planning, and in both a car is close to essential on land. The British Virgin Islands add a second layer: ferries between islands, a longer trip to Anegada, or a charter yacht that turns the getting about into the vacation itself. Saint-Martin is one island where nothing is more than a short drive away, but the traffic around Marigot and the lagoon bridges can eat into that advantage.

Saint-Martin offers far more. Marigot's waterfront market and French boutiques, then Philipsburg's long duty-free strip across the open border, make an easy afternoon. Guavaberry liqueur is the souvenir with the most local character.

In the British Virgin Islands, shopping comes down to a few shops on Road Town's Main Street and the marina stores. Anyone keen to shop ends up taking the ferry to St Thomas.

Neither is cheap, but Saint-Martin is the easier one to manage on a smaller budget. Its lolos, supermarket picnics and lower rates in late spring and summer give real ways to cut costs.

The British Virgin Islands are dearer at almost every turn, from imported food and costly taxis to the yacht charter at the heart of the classic trip. Sharing a boat or staying in a Tortola guesthouse helps only a little.

There is no theatre or concert life on either island, so music is something you hear rather than book. The British Virgin Islands have fungi, played by scratch bands on washboards and gourds, plus the Emancipation Festival in late summer. Saint-Martin leans to steel pan, zouk and soca, with Carnival and its calypso competitions as the main event.

Neither island has a bathing or spa tradition, so the real difference is how far you can get from ordinary life. In the British Virgin Islands the quiet comes from the geography. Once you leave the Road Town side of Tortola for one of the smaller islands, there is hardly any traffic. On Anegada or a remote Virgin Gorda bay, the days are shaped by swims, meals and the light. The spas are few but good, each tied to its own resort rather than part of a wider scene.

Saint-Martin's calm is found in pockets of one well-populated island, such as a cove on the west coast or a villa in the hills above Anse Marcel. It actually has more choice of treatments, with independent massage and beauty studios and beachside yoga alongside the resort spas. Still, the main road and its daily traffic are never far away, so it is harder to fully switch off.