The Beatles legend, 81, was spotted enjoying the Caribbean sun while towelling himself dry following a dip in the ocean alongside his wife of 13 years, 64.
Sporting colourful swimming shorts and a navy blue long-sleeved top, Paul looked incredibly relaxed as he frolicked in the ocean.
Meanwhile, Nancy sported a pink swirl print swimming top and black shorts as she strolled into the water for a dip.
It comes as it was reported that Paul showed his generous side by handing a family a six-figure sum to thank them for returning a £10 million guitar, after it was stolen in the 1960s.
The Beatles star , made the most of the warm temperatures on the island as he went for a boat trip with his other half, on Saturday.
Stars at St. Barts can enjoy relatively normal holiday due to minimal restrictions with restaurants, hotels and spas on the tropical island all welcoming guests.
The iconic singer went shirtless for much of the day as he went swimming with Nancy, diving off the edge of the boat numerous times.
Sporting a freshly grown beard, Paul was spotted doing the backstroke in the water before he was helped on board by boat staff members.
The couple looked in good spirits as they laughed and frolicked in the water together while making the most of their holiday. TO WATCH THE FULL GALLERY CLICK HERE
