Culebra or Saint-Martin?

Both islands are true beach destinations, and they differ in kind more than in quality. Culebra's draw is one outstanding beach, Flamenco, a horseshoe of fine white sand with the old tanks in its shallows. Around it are reef beaches near Dewey and the tidal pools of Tortuga on Culebrita. Facilities are minimal and shade is scarce, and winter swells can roughen the north-facing beaches.

Saint-Martin offers more range and more comfort. Orient Bay has sunbeds and water sports, Baie Rouge and Baie Longue on the west coast are clear and calm, and Le Galion and Pinel are gentle enough for anyone. Its weak spot is the seaweed that sometimes drifts into the Atlantic-facing bays on the east side.

Saint-Martin is the place to eat well. Grand Case alone gives you French and creole dining rooms over the water and, next to them, lolos grilling ribs and lobster at shared tables. Add bakeries with proper croissants, French cheese in the supermarkets and lunch on the beach at Orient Bay, and a week of meals has real variety.

Culebra cannot compete. Food means a few casual seafood places and food trucks in Dewey selling mofongo and empanadillas, with menus that shrink when the ferry brings less. A good grilled fish in town is the evening's highlight, and many visitors cook from a cooler.

Culebra's past is a military one and Saint-Martin's a colonial one, and you can see either in a few hours. On Culebra, a small museum in a former navy powder magazine and the painted-over tanks on Flamenco tell the story of the decades of naval bombing practice that ended in the 1970s. Add Dewey, a low fishing town built around a canal and a drawbridge, and the ruined lighthouse on Culebrita, and that is the whole list.

Saint-Martin has a little more to fill a morning. The ruins of Fort Louis look out over Marigot's harbour and lagoon, and the streets below keep their creole houses with wooden balconies. A museum follows the island from its Arawak settlers to the salt pans, and a few old plantation sites survive in the hills, though this is still not an island you visit for its history.

Culebra's evenings end with a sunset drink at an open-air bar in Dewey, sometimes with a weekend band, and the island is asleep soon after dinner. That suits people who want rest, not a night out.

Saint-Martin has real options. Long dinners in Grand Case run on into street music and terraces on busy winter nights, and Orient Bay's beach bars fill at dusk. For anything late, Simpson Bay and Maho on the Dutch side have clubs and casinos open past midnight, and Carnival brings weeks of street parties.

Culebra has the better nature, and most of it is underwater. Much of the island lies in a national wildlife refuge, the reefs of the Luis Pena reserve are among the healthiest around Puerto Rico, and green turtles and rays turn up on ordinary snorkels. In spring and summer, seabird colonies fill the outer cays and turtles come ashore to nest.

Saint-Martin has more to do on land, if not better. Forested trails climb Pic Paradis to about 424m, and Orient Bay's steady trade winds make it the island to choose for kitesurfing. Its reserve around Tintamarre and Creole Rock offers good snorkelling, but not on Culebra's level.

Saint-Martin is a hub for other islands. Calm Anguilla is a short ferry ride from Marigot and St Barths, with its harbour and boutiques, is a longer crossing. Saba and Sint Eustatius make a long day out, and Philipsburg and the low-flying planes at Maho fill an afternoon closer to base.

From Culebra, the outings are boat trips to the empty beaches of Culebrita and the cays. Vieques and the main island are close on a map, but they are hard to do in a day, so most visitors stay put.

Saint-Martin is easier with children of any age. Le Galion's reef-protected shallows and the short boat ride to Pinel suit small swimmers, villas with pools and kitchens make life simple, and the zipline park and the planes at Maho give older children something besides the sea. You will need a car.

Culebra suits a narrower family: school-age children who love snorkelling. At Tamarindo they can spot turtles from waist-deep water, and the island feels safe and slow. But there is nothing built for children and medical care is limited, and the ferry or small-plane journey is hard work with toddlers.

Neither island is easy, but the hard part comes at different stages. With Culebra it is the journey there: a ferry from Ceiba that is often full and not always on time, or a small plane. Once you arrive, everything is close, and golf carts, jeeps and shared vans cover the steep little roads.

Saint-Martin's main airport is on the Dutch side, so arrival is simpler, and the daily driving is the effort. Nearly everyone hires a car, and traffic builds around Marigot, the lagoon bridges and the causeway. The open border, at least, costs you nothing to cross.

Shopping is a minor part of a trip to either island, but on Culebra there is hardly any. Dewey has some beachwear, souvenirs and a few local artists' paintings and jewellery. Otherwise its shops are for groceries, so bring anything else with you on the crossing.

Saint-Martin's shopping is modest, but it has two sides. There is a French one in Marigot, with its waterfront market and small boutiques, and the duty-free strip of Philipsburg's Front Street across the open border. Guavaberry liqueur and local rum make souvenirs with real character, which Culebra cannot match, though much of the rest is resort clothing.

Both are expensive, but Culebra is the gentler on the budget. Prices are at US levels and boat freight adds to every bill. Still, the beaches, the snorkelling and the ferry cost little, and a rental with a kitchen keeps spending down.

Saint-Martin costs more in most respects: high Caribbean rates for rooms and villas in winter, restaurant meals at French prices or above, plus car hire and boat trips on top. Lolos and supermarket picnics help, and rates ease outside the main season.

Neither island has a theatre or a concert programme, but Saint-Martin has more music. Steel pan, zouk, soca and reggae bands play at beach bars and on Grand Case's busy evenings, and Carnival brings costumed parades and calypso competitions. On Culebra, live music is the odd weekend band in Dewey and the patron saint festival once a year.

The two are close, and they relax you in different ways. Saint-Martin has treatments, with spas in the larger resorts, massage studios and beachside yoga, and a villa above Anse Marcel or a west-coast cove for peace away from the Marigot traffic.

Culebra has almost no treatments beyond a few therapists and guesthouse yoga, but its quiet is more complete. There are no big resorts, few cars, and long, empty afternoons.