San Sebastian or Santiago de Compostela?

San Sebastian has the beach Santiago lacks. La Concha's sheltered shell of pale sand sits right in the centre, Ondarreta carries on quietly towards Monte Igueldo, and Zurriola gives surfers open Atlantic waves, all a short walk from your hotel.

Santiago is about 35km from the sea, so swimming means a day out to the white-sand inlets of the Ría de Muros e Noia or the Ría de Arousa. They are lovely and calm, but the water is colder than in the Bay of Biscay and the trip takes planning. Both seasons are short, really July and August.

Both are great regional food cities, but San Sebastian is on another level. The pintxo crawl through the Parte Vieja and Gros, with txakoli poured from height, is a reason to travel in itself, and the hills around town hold some of Spain's most celebrated fine dining, plus cider houses in Astigarraga in the first months of the year.

Santiago's strength is Galician seafood served without fuss: pulpo á feira, scallops in the shell and percebes, with the Mercado de Abastos at its centre and Albariño in the taverns of Rúa do Franco. It is generous and honest rather than inventive. Neither city offers much beyond its own region's cooking.

Santiago has much more to see. The cathedral, with the Pórtico da Gloria, the shrine of Saint James and the botafumeiro on great occasions, anchors one of Spain's grandest squares, and the granite old town of monasteries and convent squares is a UNESCO site, with the Museo do Pobo Galego and the Cidade da Cultura adding depth.

San Sebastian is a place to enjoy as a whole rather than a list of monuments: belle époque streets around the Buen Pastor, the rebuilt grid of the Parte Vieja, the castle on Monte Urgull, the San Telmo Museum and the Peine del Viento at the end of the bay. It is attractive, but lighter on landmarks.

The two are fairly level, and neither has a big club scene, but they peak at opposite times of year. San Sebastian's evenings revolve around the pintxo bars, then narrow to a few late bars and clubs, and the city stays out latest in summer, above all during the Semana Grande fireworks in August.

Santiago runs on its university, so term time is liveliest, with Thursday the student night and pub-like bars around Rúa da Raíña, some with Galician folk sessions. In summer the students leave and the early-to-bed pilgrims take over, the reverse of San Sebastian's pattern.

San Sebastian has the better outdoors on its doorstep. You can walk straight from Monte Ulia along cliffs to Pasaia and over Jaizkibel to Hondarribia, ride the funicular up Igueldo, surf at Zurriola or paddle in the bay, with Aiako Harria inland within an hour.

Santiago's countryside is gentler: oak woods and stone-walled fields crossed by the Camino paths. Its wilder scenery, the Costa da Morte cliffs, the Fragas do Eume woodland and the rías, is an hour or two away and needs a car or tour.

Both make good bases, but San Sebastian's position on the French border gives it more variety. Bilbao and the Guggenheim, Hondarribia, Pamplona and the French Basque towns of Biarritz, Bayonne and Saint-Jean-de-Luz are all an hour or so away, with Rioja Alavesa's vineyards within two hours.

Santiago's outings stay within Galicia: A Coruña and the Tower of Hercules half an hour by train, Pontevedra, Vigo, Ourense and walled Lugo. The Albariño country and the Camino's end at Fisterra and Muxía are easier by car.

San Sebastian is the easier city with children. Calm central beaches, a flat car-free promenade, the aquarium's walk-through tunnel, the hands-on Eureka museum and the old funfair at the top of the Igueldo funicular fill several days.

Santiago is safe and welcoming, but its sights are churches and museums, the cobbled hills are hard with a pushchair, and long rain can keep everyone indoors. Families usually see it in a day or two and then head for A Coruña's aquarium or the coast.

San Sebastian is a touch easier to move around. It is flat, the bay and the river link the main districts on foot, wide waterfront bike lanes help, and Euskotren trains run to the French border and towards Bilbao.

Santiago's old town is just as compact, crossed in about twenty minutes, but its granite streets climb a little and turn slippery in the rain. Trains serve the Galician cities well, yet the beaches, wine villages and Costa da Morte really call for a car or a tour.

Neither is a shopping destination, and the difference is one of kind. San Sebastian leans towards style, with independent boutiques in the Centro, espadrilles, berets and linen in the old town, and surf and design shops in Gros.

Santiago is about craft: black jet carvings near the cathedral, silver on the Praterías and blue-and-white Sargadelos ceramics, among plenty of pilgrim souvenirs. In both, the best things to take home come from the markets, preserved fish and Idiazabal in one, tetilla and tarta de Santiago in the other.

Santiago is far kinder on the budget. Tapas often come free with a drink, set lunches are generous, seafood and wine cost less than in the big cities, and pensiones and pilgrim hostels keep a stay cheap, except around the feast of Saint James in July.

San Sebastian ranks among Spain's most expensive places to sleep, with rooms scarce and summer and festival weeks especially dear, and its famous restaurants are a real splurge. A careful pintxo crawl, free beaches and walks soften the bill, and coming outside summer helps most.

Broadly level, but San Sebastian's music is concentrated in summer, with Jazzaldia in July bringing international names to the Kursaal and free concerts on Zurriola, and the Quincena Musical filling August with orchestras and opera. The rest of the year the Kursaal and the ornate Victoria Eugenia keep a modest programme.

Santiago is more about everyday tradition: bagpipe and folk sessions in old-town bars and student tunas singing in black capes, alongside the Real Filharmonía de Galicia's season at the Auditorio. It has no opera to speak of.

San Sebastian has the edge because its spa is right in town. The historic bathing pavilion on La Concha is a seawater thalassotherapy centre looking onto the bay, a legacy of its royal resort days, and the calm promenade evenings do the rest.

Santiago has only hotel spas in the city, but Galicia's hot springs are close: Caldas de Reis and Cuntis about half an hour away, and Ourense's riverside thermal pools, some free, forty minutes by train. It is a good outing for tired walking legs, though it takes a trip to get there.