Guadeloupe or Martinique?

These are two equally strong beach islands with different layouts. Guadeloupe has an almost continuous line of white-sand, reef-sheltered lagoons along Grande-Terre's south coast, from Le Gosier to Saint-François. Basse-Terre adds wilder beaches such as Grande Anse, and Les Saintes and Marie-Galante add quieter beaches again. With that much coastline, it is easy to move away from a shore hit by sargassum.

Martinique's good swimming is concentrated in the south and on the Caribbean side. Its beaches are coves rather than long strips: the palm-lined curve of Les Salines, the turtle bays of Les Anses-d'Arlet, and the black and gold sand side by side at Anse Noire and Anse Dufour. The sandbanks off Le François are a waist-deep oddity reached by boat.

Both islands cook Creole food with French bakeries alongside, so the gap is small. Guadeloupe is at its best in simple places: bokit vans by the road, lolo shacks on the beach, and colombo curries that come from its Indian heritage. Its rum trail leads to the distilleries of Marie-Galante.

Martinique takes its rum a little more formally. Its rhum agricole has its own appellation, and the old estates are set up for tastings. It also has a small fine-dining tier for a special night out, but on both islands the everyday choice soon starts to repeat itself.

Neither island makes a sightseeing trip on its own, and each has one visit that stands out. In Guadeloupe it is the Mémorial ACTe, a serious modern museum of slavery on the old sugar wharf in Pointe-à-Pitre, with forts and the windmills of Marie-Galante further out.

Martinique's equivalent is Saint-Pierre, the capital wiped out by Mount Pelée in 1902, whose ruined theatre and prison cell bring the disaster close. Fort-de-France adds the ornate Schoelcher Library, and Les Trois-Îlets has the birthplace of the Empress Joséphine.

Evenings are quiet on both islands, and you need a car to reach anything late. Guadeloupe at least has a cluster in Le Gosier, with bars, a casino and clubs playing zouk and dancehall, so a night out is easier to find.

Martinique's clubs are around Fort-de-France and draw mostly locals with zouk and kompa. The marinas at Le Marin and Les Trois-Îlets have a few livelier bars. On both islands, carnival before Lent is the time to stay out late.

The real difference outdoors is the kind of day each island gives you. Guadeloupe is best for rainforest walking and easy snorkelling, while Martinique leans towards adventure sports and time at sea. On Guadeloupe most of Basse-Terre is national park, with the steaming crater of La Soufrière at 1,467m and trails to the Carbet falls. Offshore, the Cousteau Reserve off Malendure has turtles and coral close to the beach, and the mangroves of the Grand Cul-de-Sac Marin are good for kayaking.

Martinique has Mount Pelée and the UNESCO-listed forests of the north, but it adds more active options: canyoning in the gorges, dry-forest trails along the Atlantic cliffs of the Caravelle peninsula, and wreck dives off Saint-Pierre. Sailing out of Le Marin and seasonal whale watching give it more to do on the water.

Guadeloupe is clearly ahead here, because its own archipelago is the day trip. Short ferries reach the painted fishing village and bay of Terre-de-Haut in Les Saintes, the windmills and distilleries of Marie-Galante, and the quiet of La Désirade. Each feels distinct from the main island.

Martinique's best day out is by road, a tour of the rum estates around Sainte-Marie and Le Robert, followed by drives to fishing villages like Grand-Rivière. Ferries to Dominica or St Lucia offer a change of country, but beyond those the options run short.

Guadeloupe is the easier island with children. Its south-coast lagoons are calm, warm and shallow for a long way out, and there are more small attractions within reach: the aquarium at Le Gosier, the forest zoo, the Deshaies botanical garden and boat trips to Les Saintes for older children.

Martinique's southern bays are also safe for children, and snorkelling with turtles just off the sand is a real treat. Beyond that there is little built for children, and the steep, winding drives tire them quickly, so it works best as a simple beach stay.

You will need a hire car on either island, but Guadeloupe's roads are less hard work. Most visitors stay on one wing and drive to the other, and on Les Saintes and Marie-Galante a scooter or bicycle is enough.

Martinique's northern roads are steep and twisting, and traffic around Fort-de-France and Le Lamentin is heavy at rush hour. The passenger ferries across the bay to Les Trois-Îlets and Anse Mitan help, but staying in the south still means some long drives.

Both islands have little shopping to plan a trip around, and they offer much the same things: aged rum bought at the distillery, spices and vanilla from a covered market, and madras cloth. Guadeloupe's spice market in Pointe-à-Pitre is the more colourful single stop. Martinique adds craft villages selling basketry, pottery and carved calabash.

On either island, a hire car and dear imported groceries are fixed costs you cannot avoid, so the savings come from how you sleep and eat. Guadeloupe has mostly villas, apartments and small guesthouses rather than big resorts, which suits groups sharing a kitchen, and bokit vans and lolos are cheap places to eat.

On Martinique, the cheaper way to stay is a self-catering gîte, with market produce and meals at beach snack bars, and the estate rum tastings cost little or nothing. On both islands, the winter season from December to April is the most expensive time to go.

Both islands have living drum traditions rather than a concert-hall culture. Guadeloupe's is gwoka, the UNESCO-recognised plantation drumming you can hear at léwòz evenings. L'Artchipel in Basse-Terre town and the Terre de Blues festival on Marie-Galante give it a slightly fuller calendar.

Martinique's counterpart is bèlè, and village bèlè nights often pull visitors into the dance circle. Fort-de-France has a national arts centre and a July cultural festival, though most formal performances are in French.

Guadeloupe has the stronger case, because its volcano heats the water. You can soak in the forest pools of Bains Jaunes on the way up La Soufrière, the warm rock pools at the shoreline near Bouillante, or the small thermal spa at Ravine Chaude. The empty roads of Marie-Galante make slowing down easy.

Martinique has no bathing tradition, and its few northern springs are only for a quick dip. Relaxing there means resort spas and beach yoga around Les Trois-Îlets and Sainte-Anne, and the slow rhythm of a villa on the southern Caribbean coast.