Placid Lake Colibiţa has a few row boat and kayak operators, usually attached to guesthouses. Prices start at around 20 lei per hour for a kayak.
There are six major walking trails in the wilds around Piatra Fântânele. The fairly easy 3½-hour Trail 3 winds from Piatra Fântânele village along an old Roman road; follow the red dot markings. More difficult is six-hour Trail 5 from Piatra Fântânele to Colibiţa, following the red cross markings. There's a billboard with a rough hiking map and trail lengths outside Hotel Castel Dracula.