Bella Hadid -- Hey, Gigi ... I Can Do the Swimsuit Thing Too!

Gigi Hadid is not the only girl in her family whose swimsuit game is on point ... her 18-year-old sister Bella has some mad skills of her own.

While Gigi goes around town with new man Joe Jonas, Bella is living it up in Turks and Caicos, posing for pics on the beach with a hot friend.

The greatest accessory a woman can have remains ... genes.