Kristin Cavallari, Stephanie Pratt, and Audrina Patridge led The Hills cast during a beach bikini romp in Costa Rica today. The girls, also including Stacey the waitress, hit the sand and explored a nearby waterfall with a shirtless Brody Jenner to shoot scenes from the finale episode. Audrina is newly single again after splitting with Ryan Cabrera. Also absent, of course, were Heidi Montag and Spencer Pratt, who, despite loving some skimpy two-pieces, have ostracized themselves from the rest of the crew this season. Audrina, Kristin, and Stephanie have all hosted Las Vegas pool parties already this Spring, showing off their playful hot bodies at birthday bashes, but this time it's more exotic in their Central American locale.