The mother of four, 50, was joined by her husband Tom Kaulitz, 34, for a getaway on the Caribbean island of St Barts.
At one point, Heidi lounged on a rubber reindeer, flashing her behind in a black string bikini, as rocker Tom swims up for a chat.
The pair were also seen striding hand in hand along the sands.
Heidi even posed topless on the beach in snaps she shared with fans on Instagram.
The model gushed: “What a beautiful, beautiful day.”
Project Runway alum Heidi shares 19-year-old daughter Leni with her former ex and F1 boss Flavio Briatore, 70.
She was married to Brit singer Seal between 2005 and 2014.
The pair went through a nasty divorce and custody battle after they made the decision to split in 2012.
Hedi has three kids with Seal: Henry Samuel, 18, Johan Samuel, 17, and Sulola Samuel, 14.
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