Teigen was snapped on Tuesday, December 29, in a one-piece on a boat in pictures obtained by Page Six.
Teigen left her long tresses down as she soaked up the sun and rode a jet ski with her daughter, Luna. For his part, Legend wore swim trunks that were just as bright and spent time on a kayak and snorkeling.
Teigen flashed a smile in the pics as she stood on the boat before she headed into the water for a swim. She leaned onto the deck and kept an eye on her daughter, who was wearing a lifejacket.
Teigen showed off the same swimsuit on Instagram earlier on the same day where she danced around her hotel room. "Good morning!!!" she captioned the clip.
"I need whatever drugs you’re on!!" one fan joked in the comments section, but Teigen replied that she’s actually four weeks sober and abstains from drinking as addiction runs in her family.
"So glad you're smiling again!!" one fan commented. "Love seeing Chrissy smile," another said.
Earlier in the week, Teigen opened up about her post-pregnancy body struggle after losing her son, Jack, in a heartbreaking miscarriage.
"This is me and my body … Even though I’m no longer pregnant, every glance in the mirror reminds me of what could have been," she wrote. "And I have no idea why I still have this bump, honestly. It’s frustrating."
Teigen also revealed that Jack was the couple’s last embryo, and she will never be pregnant again. Teigen and Legend have two children together — Luna and Miles.
The couple is on vacation with Teigen’s mom, Vilailuck Teigen, and several friends. St. Barts have strict tourism rules amid the coronavirus pandemic and visitors must test negative for the virus within three days of arriving or take a test upon arrival and quarantine until the results are in.