Seaside High School is a school located in Seaside, California. The school first opened in September 1963 to sophomores and juniors (incoming seniors continued to attend Monterey High School until graduation), graduating its first class in June 1965. Average annual enrollment is 1,400 students, attending grades 9–12. The school serves the communities of Seaside, Monterey, Marina, Sand City, and Del Rey Oaks. Its student body reflects the region's diversity of language, ethnicity, nationality, and cultures. The school mascot is the Spartan.