Siesta Key Beach is the main event — the sand is nearly pure quartz, which means it stays cool even in high summer and has an almost powdery texture underfoot. The Gulf is calm and warm, with very gentle waves. It gets crowded on weekends and throughout winter, but the beach is wide enough to absorb it. Parking at the main beach lot fills early; arrive before 10am in peak season or use the side streets. Crescent Beach, further south on Siesta Key, is quieter.
Lido Beach on Lido Key is closer to downtown and St. Armands Circle, and tends to draw a more local crowd. Not as dramatic as Siesta Key but perfectly pleasant, with better nearby restaurants.