Pippa Middleton's latest vacation photos showed how a 40-year-old mom of three could still rock a bikini.

A day before Valentine's Day, Pippa, her husband James Matthews and their three children -- Arthur, 5, Grace, 2, and Rose, 1 -- were spotted vacationing in St. Barts. They stayed at Eden Rock, the pricey hotel of Matthews' parents, per Page Six.

During their vacation, the younger sister of Kate Middleton was photographed wearing a bright green bikini, which showcased her toned physique.

A post shared by instagram

According to the Royal Fashion Police on Instagram, the British socialite wore a $340 bikini top and bottom from Vix Paula Hermanny Brasil, which she paired with £289 (~$364) Jimmy Choo sunglasses.

Seeing a compilation of her bikini-clad photos, some netizens commented on Pippa's physique and choice of beach outfit.

"I'd love a copy of her diet and exercise regimen, just to look at. I doubt I'd have the willpower to actually do it," one user quipped.

"Pippa works out super hard and is also genetic goals," commented a second netizen.

"Excellent! [I] love the pop of color," said a third user.

Interestingly, this was not the first time Pippa was photographed wearing a two-piece. In February 2023, just five months after giving birth to their third child Rose, Princess Catherine's sister was snapped rocking a red bikini while on vacation.

In the photos that circulated online, the mom of three was seen walking alongside her husband while carrying a little blue pail.

Pippa Middleton
(Photo : Jeff J Mitchell/Getty Images)
Pippa Middleton departs the Coronation of King Charles III and Queen Camilla on May 06, 2023 in London, England.

Meanwhile, in a "rare interview" with Cosmopolitan in 2021, Pippa shared details about how she managed to stay physically fit as a mom.

She revealed that her love for running helped her stay in shape despite having such a busy day-to-day, as well as clear her thoughts in times of stress.

"Running and sport, in general, has been a constant light in my life," she said.

She also disclosed that looking after her son helped maintain her weight since she and her child loved exploring the great outdoors.

"Being active with my two and a half year old son in the park or playground, transporting him on the back of my bike and buggy running when he was a baby have been ways in which I have been able to include outdoor exercise whilst being a hands-on mummy," she shared at the time.