Biarritz or San Sebastian?

The two are evenly matched for beaches, but they offer very different swimming. Biarritz faces the open Atlantic, so the Grande Plage, the Côte des Basques and the long Anglet sands bring surf and strong currents, and only the small Port Vieux cove is truly calm.

San Sebastian's La Concha is a sheltered bay in the middle of the city, with quiet water and Ondarreta beside it, while Zurriola is the beach for waves. The sea is equally cool at both outside high summer.

Both cook Basque, but San Sebastian takes food much further. Biarritz eats well around Les Halles, with pintxos at the market bars, Bayonne ham and Espelette pepper. Away from the market, though, the choice is that of a smart resort, and the seafront has ordinary tourist places.

In San Sebastian the pintxo crawl through the Parte Vieja and Gros is the main event of the evening. Above it sit some of Spain's most celebrated restaurants, and between January and spring there are the cider houses of Astigarraga.

Biarritz's sights are the resort itself: the former imperial villa, the Art Deco casino, the Russian Orthodox church and the footbridge out to the Rocher de la Vierge. Its museums are the aquarium and the ocean centre, so anyone who wants serious history will be heading to Bayonne.

San Sebastian gives a culture lover more to work with. There is the old grid of the Parte Vieja leading to the baroque Basilica of Santa Maria, the castle on Monte Urgull, the San Telmo Museum of Basque society and Chillida's Peine del Viento in the rocks at Ondarreta.

Neither is a clubbing destination, and both get quiet midweek out of season. In summer, Biarritz's evenings centre on wine and pintxos around Les Halles, sundowners above the Côte des Basques and the casino.

San Sebastian has more going on. The old town's bars fill from early evening and stay loud until late at weekends, students keep a few late bars busy, and the August Semana Grande, with nightly fireworks over the bay, keeps the city out much later. Biarritz's own crowd often crosses the border for exactly this.

Both are green, rainy and good for the outdoors, but the emphasis differs. Biarritz is above all a surf town, with beginner breaks, reef waves further down the coast and surf schools along the front. The Pyrenean foothills and La Rhune's rack railway are about half an hour inland.

San Sebastian is better for walking straight from town. Its ring of hills leads onto the cliff path from Monte Ulia to Pasaia and over Jaizkibel to Hondarribia, and calm paddling in the bay complements the surf at Zurriola.

Each town is one of the other's best day trips, under an hour apart, and both have a fine choice of outings in two countries. From Biarritz the strength is the French Basque interior: Espelette, Ainhoa, Sare and walled Saint-Jean-Pied-de-Port, several of which are easier with a car.

San Sebastian looks towards Spain. Bilbao and the Guggenheim are a bus ride away, and Pamplona, Getaria and the Rioja Alavesa vineyards are all within reach. More of its trips work without driving.

Both are safe, small and pleasant with children, with an aquarium in each and only a few days' worth of attractions. Biarritz offers surf lessons and the Cité de l'Océan, but its main beaches have big waves, and the steep streets are hard going with a pushchair.

San Sebastian is gentler for small children. Its central beaches are calm, the promenade is flat and car-free, and there are the hands-on Eureka museum and the old funfair on Monte Igueldo. The trade-off is rainy spells that can rule out the beach for days.

San Sebastian is much easier to get around. It is flat, the old town, La Concha and Gros are minutes apart, bike lanes follow the waterfront, and Euskotren trains run east to France and west towards Bilbao.

Biarritz is walkable too, but its streets and steps climb steeply between the cliffs and the beaches. The airport on the edge of town is handy, though most visitors hire a car for the villages and mountains.

Neither is a shopping destination, and both lack department stores. The best buys are local in both. In Biarritz that means chocolatiers, gâteau basque, striped Basque linen and espadrilles, plus fashion and surf boutiques near the Place Clemenceau.

San Sebastian adds Spanish fashion chains in the Centro. Its edible souvenirs are Idiazabal cheese, txakoli and tinned anchovies and bonito from the markets and old grocers.

Both are expensive, especially in July and August, and the cheapest way to eat in either is at a pintxo counter. Biarritz has the easier escape: staying in Anglet or Bayonne and travelling in costs noticeably less.

San Sebastian's rooms are scarce, and in festival weeks they reach big-capital levels. Its famous restaurants are a real splurge, though the beaches, the hill walks and the cheap city buses cost little.

San Sebastian has the stronger programme, though it is concentrated in summer. Jazzaldia brings international jazz to the Kursaal and free concerts to Zurriola in July, and the Quincena Musical fills August with orchestral music and opera. The 1912 Teatro Victoria Eugenia stages plays and dance for the rest of the year.

Biarritz's one real strength is dance. Its national choreographic centre and ballet company perform at the Gare du Midi, and there is an autumn dance festival, but there is no opera house and little live music.

Biarritz is the place to come for treatment. It is one of the homes of French thalassotherapy, and its several large seafront spas run multi-day seawater cures that people book as the purpose of a vacation.

San Sebastian has the historic bathing pavilion on La Concha, now a seawater spa looking onto the bay, but beyond that it is mostly hotel spas. Its calm, orderly pace and evening walks along the promenade are still very restful.