Check out these pics of bikini-clad Rihanna as she roars around on the back of pro surfer Makua Rothman’s Kawasaki watercraft and continues to celebrate her 25th birthday.

The incredibly talented artist known for hits such as “Umbrella,” “Where Have You Been, and “Diamonds” showed off her bikini body as she indulged in her favorite pastime. Make-up free and her hair drenched with water, the pop star was seen holding onto the back of the jet-ski as Rothman sped around the Hawaiian waters, having a ball with the world champion Hawaiian big wave surfer, musician and actor.

Makua began surfing at the early age of two years old, but began tow-in surfing at the age of 13 when his dad and family friend Darrick Doerner, a pioneer in tow-in surfing, first taught Makua. Makua eventually learned the ropes of tow-in surfing and in 2002 won the Billabong XXL Big Wave Challenge Award in one of the most historic big-wave sessions in history. His fearless surfing of the 66 foot wave earned him $66,000, a thousand dollars for every foot. It was the largest wave in the world to be surfed that winter. Makua is currently sponsored by RVCA.

Happy Birthday Riri!