• Train from Passeig de Gràcia or Sants runs every 20-30 min and takes about 50 minutes, with the station a 10-minute walk from the beach
• Sant Sebastià beach is the calmest family stretch, sheltered by breakwaters with shallow water and a lifeguard in summer
• Flat and walkable, so the promenade and old quarter work fine with a stroller between beach and ice-cream stops

A 50-minute train ride south of the city reaches a small seaside town with 17 sandy beaches strung along a 4km promenade. Breakwaters keep the water calm and shallow, several beaches have lifeguards and pedalo hire, and the flat old quarter behind the seafront has ice-cream shops, a hilltop church, and easy streets for strollers.