Rita Ora's Bikini is Barely Holding On in Ibiza

Rita Ora's hot girl summer leaves very little to the imagination ... not that we think anyone's complaining.

The pop singer and actor's been enjoying the luxury lifestyle in Ibiza with friends this week, while her string bikini selections defy the laws of physics.

This one in particular -- a black 2-piece with a singular red star on the bottoms to match her nearby tattoo -- appears to be at least a couple sizes too small. Just the way Rita likes it.

Despite the barely-there swimwear, Ora doesn't seem to have any pause about taking a plunge into the sea ... wardrobe malfunctions be damned.

Inhibitions tend to be thrown to the wind when one's balling out on a yacht ... but Rita's next level.