The actress wore a two-piece blue and white swimsuit that showed off her slender figure. Her boyfriend showed off his fit body in blue and orange trunks.
At one point Rumer was seen reading erotic novel "Fifty Shades of Freed," the third novel of the "Fifty Shades of Grey" series. Demi Moore and Bruce Willis' daughter performed in public for the first time with her band at the new SLS Hotel on Miami Beach.
Rumer stars in several upcoming films, including "The Odd Way Home" and "The Ganzfeld Experiment."
See more photos of Rumer and her boyfriend...