Credit: kimkardashian/Instagram

North West and Penelope Disick's annual joint birthday party is always a FOMO-inducing affair, and this year is no exception. This weekend, Kim Kardashian West's 4-year-old daughter and Kourtney Kardashian's soon-to-be 5-year-old daughter partied with all their friends at a Moana-themed birthday bash, and it looked like a pretty epic event.

Last year, North and Penelope had a mermaid party for their birthdays, dressing up in sparkling tails and making Auntie Khloé wear a purple wig. This year, the two mini-starlets went the Disney route for their bash, donning their best Polynesian-inspired outfits to celebrate like Moana. Guests wore flowery leis, and North even rocked a tropical flower crown. (North already partied at Chuck E. Cheese's on her actual birthday, but it seems that was only a prelude to things to come.)

VIDEO: Happy 4th Birthday, North West!

In addition to splashing around in the pool, the kids also played on a blow-up surfboard ride. Kourtney and her friends couldn't resist a photo op with the ocean-themed toy, posing together on the surfboard in this cute 'Gram.

And, of course, no Kardahsian party is complete without an extravagant cake—or two! The family got two matching triple-decker cakes for their little ladies, and each dessert is decorated to match the tropical theme.

Credit: KhloeKardashian / Snapchat

In addition to having a joint party, North and Penelope also got matching puppies for their birthdays! These two are seriously the cutest.