San Onofre State Beach features 3.5-miles of sandy beaches with six access trails cut into the bluff above. The campground is along Old Highway 101 adjacent to the sandstone bluffs. The beach is popular with swimmers and surfers. The park includes a marshy area where San Mateo Creek meets the shoreline and Trestles Beach, a well-known California surfing site. Whales, dolphins and sea lions can be seen offshore from time to time. The park’s coastal terrace is chaparral-covered.
San Onofre includes San Onofre Surf Beach - a day use facility, San Mateo campground and day use facility, and a Nature Trail that starts at San Mateo Canyon and leads to San Mateo State Preserve/ Trestles Beach.

Located between San Onofre SB and San Onfore Surf Beach is San Onofre Nuclear Generating Station (SONGS) provides nearly 20-percent of the power to more than 15-million people in Southern California.

Trestles Beach is regarded as one of the premiere surf breaks in the United States. Many would say the best in San Diego County.