Kourtney Kardashian, 41, appears youthful as she lounges at home in her bikini

Kourtney Kardashian, 41, appears youthful as she lounges at home in her bikini: ‘Evolve as you please’

Kourtney Kardashian shared a pinup photo that made her look much younger than her 41 years.

The Keeping Up with The Kardashians veteran was lounging around the backyard of her Calabasas, California mansion for the snapshot.

‘Evolve as you please,’ the mother-of-three wrote in her caption.

Relaxed: Kourtney Kardashian shared a pinup photo that made her look much younger than her 41 years. The Keeping Up with The Kardashians vet was lounging around her Calabasas, California mansion for the snapshot

The bigger picture: 'Evolve as you please,' the mother-of-three wrote in her caption

The bigger picture: ‘Evolve as you please,’ the mother-of-three wrote in her caption

She certainly seems to have a thing for swimwear photos.    

To celebrate her 41st birthday, the sister of Kim and Khloe was seen in a flashback photo from 25 years ago when she posed in a black-and-white two piece.

The petite wonder seemed to be at her hotel while on vacation in Hawaii.

The college graduate had her dark hair worn short and partially pulled back. There was heavy eye makeup on for the portrait as well as frosty beige lipstick.

Her arms were up on the balcony rail as she seemed to be impressed with her deep tan as she wore a black and white striped suit.

Teen Kourtney: Here Ms Kardashian is seen about 25 years ago; the image was shared as the Poosh founder celebrated her 41st birthday

Teen Kourtney: Here Ms Kardashian is seen about 25 years ago; the image was shared as the Poosh founder celebrated her 41st birthday

But she looks even better nowadays: The siren, left, has abs in her 40s; seen with sister Kendall Jenner, a Vogue model

But she looks even better nowadays: The siren, left, has abs in her 40s; seen with sister Kendall Jenner, a Vogue model

The POOSH founder’s body looks great, but she actually may look even better now.

Also this weekend, her supermodel sister Kendall Jenner shared a recent shot from a bikini modeling session.

Kourtney was in a black and beige leopard print suit with her hair in a turban – she was showing off a more muscular frame with abs and sculpted legs.

Her little sister was in something similar as she squatted down.

Later: And there was another image of Kourtney in a purple bikini shared by Kim; the era seemed to be about 10 years ago

Later: And there was another image of Kourtney in a purple bikini shared by Kim; the era seemed to be about 10 years ago

Drama: Kourtney was recently told she looked pregnant in this image. The star replied to fans that she liked her more womanly body

Drama: Kourtney was recently told she looked pregnant in this image. The star replied to fans that she liked her more womanly body

And there was another image of Kourtney in a purple bikini shared by Kim; the era seemed to be about 10 years ago. 

Kim shared a gushing 41st birthday tribute to her sister Kourtney.

The 39-year-old reality TV icon fired up her Instagram to post a string of throwback snaps of the pair of them together.

‘Happy Birthday @kourtneykardashian I had to find some good throwbacks to celebrate you today! I remember these moments so vividly,’ wrote Kim.

How she stays in such great shape: The eldest Kardashian works out every morning

How she stays in such great shape: The eldest Kardashian works out every morning

‘I love your strong will to do whatever makes your soul happy, the love you have for you children and for being the best big sister,’ she gushed.

‘I couldn’t be more thankful for our memories together. You pack a mean punch I love you so much and can’t wait until this is all over so we can celebrate together.’

Kim and Kourtney are the eldest two children of Kris Jenner and her first husband, the late O.J. Simpson lawyer Robert Kardashian.

The throwback snaps Kim posted on Saturday included not just Kim and Kourtney, but in some cases their sister Khloe and their mother as well.

A couple of sweet childhood pictures showed Kim and Kourtney together such as one where they were dressed up in matching striped shirts.

One picture was a solo shot of Kourtney who showed off her bombshell beach body in a barely-there purple bikini.