• Shallow, gentle water that stays waist-deep well out from shore, calmer than the city beaches for young swimmers
• Watersports schools on the sand for sailing, windsurfing, kitesurfing and paddleboarding, with kit hire on site
• Summer lifeguards staff the main bathing zones from June to September, plus playgrounds and a seasonal tourist train

Castelldefels runs for nearly 5 kilometers of wide, flat golden sand about 18 km south of the city, reaching 90 meters across at its widest. The sea stays shallow a long way out, and the steady afternoon breeze feeds sailing, windsurfing, kitesurfing and paddleboard schools along the promenade. Kids find playgrounds, sports courts, chiringuitos and a summer tourist train, with lifeguards on the main bathing zones from June to September.