Penguins is a swim school built only for babies, kids and expecting mothers, with small warm pools, salt-treated water and levels named after penguin colors that children move up through. Classes are 40 minutes, once a week and in small groups, from water-familiarity sessions for babies with a parent in the pool to stroke technique and squad-style training for older kids. Three of the four centers are in Barcelona — Bonanova, Tuset and the Betània-Patmos school in Sarrià — and the fourth is in Sant Cugat del Vallès, outside the city.