Livvy Dunne vs. Anastasia Ashley Who'd You Rather?! (Athletes In Black Bikinis Edition)

Livvy Dunne and Anastasia Ashley are painting the beaches black in their skimpiest bikinis ... showing off in a pair of tiny black swimsuits -- and, we gotta know the answer to the age-old question, Who'd You Rather?

These mouthwatering pics come from videos Livvy and Anastasia dropped on their respective social media accounts ... with Livvy mouthing along to audio from the Pixar flick "Luca" before tossing herself into some crisp water.

Meanwhile, Anastasia stayed on dry land ... posing on the balcony of some resort while Kodak Black's "Transportation" played over the clip.

Livvy and Anastasia really traded environments for their respective clips ... 'cause Dunne's used to performing on dry land for gymnastics -- while Ashley's got no issue splashing around in the waves as a pro surfer.

Worth noting ... tons of celebs whip out black bikinis for their hottest pics -- click through the gallery to see each and every one.

Now, for the task at hand ... only one athlete in black swimwear can win gold -- cast your vote below!