Kourtney Kardashian rang in her 38th birthday earlier this month and celebrated with a girls-only trip to Tulum, Mexico. The eldest Kardashian had the company of her sister Kim as well as close friends Stephanie Sheppard, Malika Haqq, Brittny Gastineau, and Larsa Pippen. On Monday, the ladies bared it all in tiny bikinis — Kourtney showed a ton of underboob while Kim's greatest asset was on display in a vintage Dior two-piece — and appeared to have a blast while splashing and posing for photos in the ocean. Kim later shared some pretty wild tales about the, um, activities going on via Twitter, while Kourtney shared a couple of racy snaps on Instagram. Later in the week, the sisters were out and about again, flaunting their fit figures in sequined swimsuits on the beach at Joe Francis's Casa Aramara in Punta Mita.
The girls' beach trip comes on the heels of big news for Kim, who recently announced her plans to collaborate with sister Kylie Jenner on a collection for Kylie Cosmetics. Both Kim and Kourtney also hit the red carpet along with Cher for the LA premiere of The Promise, which follows a love triangle during the Armenian Genocide.