Inside North West and Penelope Disick's Mermaid Birthday Party

— -- Happy birthday North West and Penelope Disick!

The daughters of Kim and Kourtney Kardashian, respectively, celebrated their birthdays Saturday with a mermaid-themed party in California.

West turned 3 on June 15, while Disick is set to turn the big 4 on July 8.

The two Kardashian-clan tots wore matching mermaid costumes for their party and blew out candles on "The Little Mermaid"-themed birthday cakes.

Guests included the girls' proud fathers, Kanye West and Scott Disick, and even Ariel from "The Little Mermaid." Also spotted at the fete were the birthday girls' aunts: Khloe Kardashian and Kylie Jenner.