Britney Spears with the kids

Britney Spears and her boys hit the harbor in Sydney, Australia. The 27-year-old pop princess and BF Jason Trawick spent three hours cruising and having fun together.

Jayden, 3, and Jason played hide and seek, while Jason played Superman with Sean, 4. Mama Britney, who wore a bikini and covered up with Jason's polo shirt later, watched and smiled. The Australia leg of Brit's Circus tour is nearly halfway over - she'll tour Down Under through November