Stars Going Green Bikinis ... Happy Earth Week!

It's always important to take care of our home planet ... not just during Earth Week ... by going green, conserving water, and trying to reduce our carbon footprint, so we whipped up some stars in green swimsuits to raise your awareness.

Yes, California is a green state, so most celebs put their best (green) thumb forward, and for celebs like Kylie and Kendall Jenner, Hailey Bieber and Ariana Grande ... well you can always count on them for repping their itsy bitsy teenie weenie green bikinis.