Deputies have released a composite sketch, hoping it will help them find the suspect.
The girls say the man approached them at Wolf Creek Park on Sept. 30.
One of the females entered the park around 3:20 p.m. and was immediately harassed by the suspect. The second female walked onto the park's ground around 4 p.m. and was quickly confronted by the same male adult.
In both incidents, the suspect immediately made suggestive sexual comments. Both of the young females were able to get away unharmed.
The man was described as a Hispanic man in his early 20s, standing about 5 feet 10 inches tall with a thin build and short dark hair. The suspect was last seen wearing a gray and purple-colored short sleeve shirt with stripes, dark-colored pants and Vans sneakers.
Anyone with information on the suspect was urged to contact the Riverside County Sheriff's Department at (951) 696-3000.