The Bajan songstress, 25, has been sunning herself and working hard in Brazil for the last week, posing in swimsuits for a high profile magazine shoot and attending business meeting with fellow singer Shakira, who she has recently collaborated with on a new single.
But in true RiRi fashion, it seems she has been playing as hard as she works and couldn't resist taking a few photos of herself looking majorly hot in a revealing string bikini.
In one picture, Rihanna can be seen wearing the teeny black two piece with a delicate gold chain around her waist and holding onto a metallic bag full of her clothes.
Her large Egyptian chest tattoo is on full display, as is her latest Maori hand tattoo, which was initially etched onto her skin in Auckland, New Zealand last year, before being completed in New York.
RiRi appears to be make-up free in the snap and her long black hair extensions have been left natural.
What a babe!
The chart-topper uploaded another provocative snap, in which her long locks have been soaked with water to make it seem as though she's fresh from a swim and in a third photo, Rihanna has a playful moment on a tiny trampoline with her best friend Jen.
Rihanna and Shakira released their brand new single 'Can't Remember To Forget You' earlier this week and have been promoting the track at every opportunity.
And Colombian pop star Shakira can't believe her luck to have finally teamed up with RiRi for a fun and sexy musical offering.
She told Ryan Seacrest: "[Rihanna] heard the record and she loved it and she said she was onboard, and I was the happiest girl alive. To shoot the video with her has been a blast."
'Can't Remember To Forget You' has already received lots of support from fans, as well as praise from pop superstar Britney Spears.
Yesterday (16 January), Britney tweeted: " #nowplaying @shakira & @rihanna 'Can't Remember to Forget You'....love it! So glad you ladies joined forces!"
What do you think of Rihanna's bikini selfies? Let us know below, as the best comment from across the website each week wins £50!
Check out more snaps of RiRi in a Bikini in our gallery.