The 28-year-old Victoria's Secret model frolicked in the surf with husband Sunnery James, striking several poses for their friend's camera and making the most of her super-toned body.
Doutzen's ridic six pack made it hard to believe that she gave birth to son Phyllon just two years ago - but it didn't come without effort.
She recently admitted that she sticks to a strict 'moderation' diet to keep her weight down, eating mainly protein and vegetables - despite chips being her biggest weakness.
She said: "I always eat in moderation. If I order French fries I have a salad and I share [the fries] with my friends.
"I don't tell myself to not eat anything to stay away from all sugar or all fries or all the good fried foods. But I eat it in moderation.
"For a flat stomach in general, I stick to things like no alcohol and no onions or broccoli - they make you feel bloated ... But my stomach has never been my problem area… that's just a little bit of luck!"
Doutzen, who has been a Victoria's Secret Angel for over six years, also takes part in serious gym workouts with her personal trainer, releasing a clip of her 'sexy bum workout' in 2011.
The model's bum was the talk of the VS show last year, making headlines just for its peachiness as she posed in a pink pom-pom lingerie set.
She recently told Vogue: "I realise I am in a privileged position because it's my job to look this way and go to the gym. When I had my son, I was working out all the time like crazy.
"When I am in NYC I always go for a run outside, along the Hudson River, and I really love that. But I also do lots of boxing and jump rope training.
"I love to really sweat and have a tough workout and so my best workouts are mostly cardio. They do good but they make you feel good at the same time.
"I do Pilates for stretching and posture, but I don't really like it. I bring my jump rope with me everywhere I go."
She and husband Sunnery, who have been married for three years, spent the afternoon on the beach before heading out to his show at the LIV nightclub in Miami.
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