South-western of Sitges are some small coves with clothing-optional beaches.
The gay beach l'Home Mort (with beach bar) is approx. 4 km from the center of Sitges. To get to this beach you have to walk along the railway track for the last kilometer – so look out for the fast trains!
Bring enough water and food.
On the other side of the railway track there is some outdoor cruising in the woods.