Cameron Diaz and Drew Barrymore in Mexico on March 5, 2013. Credit: XPOSUREPHOTOS.COM

Sounds like the ultimate girls' weekend! Five months after welcoming daughter Olive, Drew Barrymore slipped into a one-piece swimsuit and hit the surf at the Amansala Resort in Tulum, Mexico -- with BFF Cameron Diaz at her side.

Barrymore, 38, and her Charlie's Angels costar Diaz, 40, were snapped smiling and relaxing in the surf with another pal; Diaz showed off her famously toned figure in a skimpy two-piece bikini. Also along for the trip? Fellow new mom Reese Witherspoon, who gave birth to her third child, son Tennessee just days before Barrymore welcome Olive.

"Reese and Drew have bonded over their babies and losing the baby weight," a source told Us Weekly of the A-list retreat in Tulum, where stars like Demi Moore have also vacationed. Staying for an extended long weekend, the trio and other other friends did yoga, ran on the beach, swam and noshed on healthy meals throughout the trip.

"All the girls were very social and had a great bonding experience," the source added of the getaway.