Guarujá is a beach city on the São Paulo coast, the closest major beach destination to São Paulo — about 85 kilometres southeast via the Anchieta highway. Paulistanos flood here on weekends and holidays, which tells you both that the beaches are good and that the crowds can be intense.
The island (technically it sits on Santo Amaro island) has over 20 beaches. Pitangueiras is the busiest — urban, lined with high-rises, packed in summer. Enseada is long and family-friendly. For quieter options, head to Praia do Tombo or Praia Branca, the latter accessible only by boat or trail. The Praia de São Pedro has good surf.
Guarujá was fashionable with São Paulo's elite in the mid-20th century, and some faded glamour remains in the larger beachfront apartment buildings. The Forte dos Andradas, a 17th-century Portuguese fort on the southern headland, is worth the trip for the views. The Aquário de Santos is actually nearby in Santos, and the ferry crossing between the two cities is a pleasant short ride. The town is practical rather than charming — a weekend beach escape rather than a destination — but the coastline is genuinely attractive.