The 33-year-old star revealed the full extent of her 44lbs weight loss as she paraded her trim figure and toned limbs as she relaxed poolside in Miami, reported Daily Mail.
Emerging from a picturesque infinity pool with the city skyline in the background, the mother-of-two showed off her tan in fuchsia, cobalt blue and gold halterneck bikinis.
Kourtney and her partner Scott Disick are already proud parents to adorable three-year-old son Mason, and welcomed Penelope Scotland into the world in July 2012.
But the eldest Kardashian sister admitted it was more difficult to lose her post-pregnancy weight the second time around.
"It was harder to lose weight the second time around. I gained 45 pounds with Penelope. It took me twice as long as last time but I feel healthy and really much better about it," she said.