Formentera or Menorca?

Both islands have Caribbean-coloured water, but Formentera's beaches are the more striking. Ses Illetes is a narrow spit of white sand with shallow turquoise sea on both sides, and the long arc of Migjorn gives you kilometres of dune to spread out on.

Menorca's best swimming is in coves rather than long strands. Macarella, Turqueta and Mitjana sit between pine-clad cliffs on the south coast, and the north has red-sand bays like Cala Pregonda. They are lovely, but they fill by late morning in summer and often need a shuttle bus or a walk in.

Lobster stew turns up on both islands, but Menorca has more of a food culture around it. Fornells is the place for caldereta de langosta, and Mahón cheese, sobrassada, ensaïmadas and pomada are everyday fare. There are quayside tapas bars in both towns and cheese sold at farm doors inland.

On Formentera, eating mostly means long lunches at beach restaurants above Migjorn and Ses Illetes, with grilled fish, rice dishes and island dishes made with peix sec. Away from the sand the choice in Sant Francesc and Es Pujols is thin.

This is where the islands differ most. Menorca has hundreds of Bronze Age monuments in open farmland, among them the Naveta des Tudons and the taula sanctuaries at Torralba d'en Salord. On top of that come Ciutadella's Gothic cathedral and palaces, and Mahón's British-era streets above a great natural harbour.

Formentera's sights add up to the fortified church in Sant Francesc, a few watchtowers, two lighthouses and the small megalithic tomb of Ca na Costa. You can see all of it in a day between swims.

Neither island is a party destination, and evenings on both run to drinks rather than dancing. Formentera's ritual is sunset at the west-coast beach bars, then a small cluster of bars in Es Pujols. For proper clubbing you cross to Ibiza and plan around the last ferry back.

Menorca's going-out happens on the harbour quays of Ciutadella and Mahón, plus a club set in a sea cave near Cala en Porter. Its real nights out are the summer town festes, above all Sant Joan in Ciutadella, with horses rearing through the crowds.

Menorca has more to explore on land. The whole island is a biosphere reserve, and the Camí de Cavalls circles it for about 185km past cliffs, coves and gorges like the Barranc d'Algendar, with the S'Albufera des Grau wetland for birdwatching.

Formentera is flatter and barer: salt pans, juniper scrub and dunes, with cliffs only at La Mola. Its strengths are the Posidonia meadows that make snorkelling and diving superb, flamingos on Estany Pudent, and green routes you can cycle almost anywhere.

Neither island offers much, but the outings differ in kind. From Formentera the obvious trip is Ibiza, only half an hour by fast ferry, for the walled hilltop of Dalt Vila and the villages beyond. A boat out to the uninhabited islet of Espalmador fills a half day.

Menorca's outings mostly stay on the island: a day in whichever of Ciutadella or Mahón you are not staying in, or a stop in Fornells or Binibeca. Mallorca is a long ferry ride away, which makes it a stretch for a single day.

Menorca is the more practical choice with children. It has an airport of its own, low-rise resorts built for families beside sheltered bays such as Arenal d'en Castell, and a small water park and farm parks for a change from the beach.

Formentera's calm shallows at Ses Illetes are ideal for paddling, and older children love cycling the flat lanes. But there is little shade, nothing made for children, and the flight to Ibiza plus a ferry is a tiring way to arrive with little ones.

Formentera is only about 20km long and is best explored on two wheels. You arrive by ferry at La Savina, and from there a hired bike, e-bike or scooter takes you almost everywhere on flat, quiet roads. Buses link the main villages and beaches, but the service is limited, and parking at the popular beaches is tight in summer.

Menorca is larger but easier to reach and to drive around. One main road links Mahón and Ciutadella, most drives take well under an hour, and summer buses serve the resorts. The wilder coves still need a car or a walk in.

Neither island has fashion streets, but Menorca gives you more to bring home. There are avarques sandals and leather goods made in Ciutadella and Alaior, Mahón cheese and local gin, and a covered market in an old cloister in Mahón.

Formentera's shopping is the summer artisans' market at El Pilar de La Mola, with handmade leather, silver and ceramics, along with a few linen and beachwear boutiques in Sant Francesc.

Both are expensive in summer, but Formentera is the harder on your wallet. It has few rooms, beach restaurants charge resort prices, and the ferry and vehicle hire add to the bill. There is no cheap way to do it in high season.

Menorca leaves more room to save. You can rent an apartment, eat in inland towns like Alaior or Es Mercadal, and visit prehistoric sites that cost little or nothing to enter.

Menorca has a small but genuine stage life where Formentera has almost none. Mahón's Teatre Principal dates from 1829 and is among Spain's oldest opera houses, Santa Maria church gives summer organ recitals, and Ciutadella hosts a classical festival.

On Formentera, live music means musicians at the La Mola market and sunset sets at a few beach bars.

The two are much alike here. Neither has thermal baths or a spa culture, and on both the restful part is the slow pace, with yoga and massage easy to find in summer.

The difference is in the setting. Formentera is smaller and more stripped back, with no high-rises and days that end early. Menorca's calm comes from converted farmhouses and rural estates, some with their own spas, and slow evenings on the harbours.