Break out your bikini and celebrate the first day of Summer! We're gearing up for the temperatures to rise with a look back at the last month's hottest bikini and shirtless  stars. Some of our favorite celebrities revealed their enviable bodies with swimsuit-filled vacations, family trips to the beach, and sexy photo shoots, including Gisele Bundchen, Andrew Garfield, Kim Kardashian , and more. Check out our roundup as you kick off your own Summer celebrations this week — surf's up!
Gisele Bundchen wore a teeny bikini during a romantic Mexican getaway with Tom Brady .
Audrina Patridge  picked a tropical print for a trip to Mexico.
Selena Gomez  and Justin Bieber escaped to Hawaii and hit the beach for some PDA under the sun.
Rachel Bilson  slipped into a simple black two-piece during a getaway to Barbados.
Hot, Hot, Hot!
Kim Kardashian  and Kris Humphries held hands walking on the beach in Bora Bora.
Sexy and Single
Bar Refaeli  showed off her incredible bod on a yacht anchored off the coast of Cannes.
Gavin Rossdale  and Gwen Stefani  took in the view off the coast of Cannes.
Courteney Cox  showed off her best assets during a visit to St. Barts.
Shia LaBeouf  got some relief from the heat by shedding his shirt during a recent stroll with his girlfriend, Karolyn Pho.
Katie Holmes  joined Suri Cruise in the majestic Miami surf.
Andrew Garfield gave us a glimpse of his six-pack during a recent trip to Hawaii.
Katherine Heigl  returned to her Miami hotel in a black sarong.
Tom Brady  zoomed down a water slide during his Mexican vacation.
Ready to Rock
Rock of Ages stars Julianne Hough and Diego Boneta perfected their tans on the Miami set.
Jude Law  was at the Eden Roc Hotel after fulfilling his Cannes Film Festival duties.
Elisabetta Canalis worked on her tan and relaxed with a beverage during a stay in Cannes.
David Beckham  stripped down to his shorts after an LA Galaxy win in front of the home crowd.
Lady of the Mist
Serena Williams splashed in the waves in Miami during her April trip to the shore.
Garrett Hedlund took a stroll on the beach in Hawaii.
Alessandra Ambrosio spent Memorial Day weekend at the beach in Malibu with her daughter, Anja, and their adorable white pup.
Making a Splash
Princess Beatrice let loose in her black bikini on a yacht docked near Cap d'Antibes.
Michelle Rodriguez joined friends for an exotic getaway to Formentera, Spain.
Stephanie Pratt popped up in Hawaii wearing a trendy, colorful bikini.
Shades of Blue
Lindsay Lohan  kept her turquoise jewelry on for a dip in the water during a trip to Miami.
Heidi Montag  showed off her assets and shared a fruit basket with friends during a Vegas pool party.