The number of students decreased, prompting the district to close Aviation High School in 1982.
[6] In 1991 the elementary school districts within South Bay Union HSD had plans to unify into a single K-12 school district.
[6] In November 1992 residents of the district approved Proposition V by 59.1%, which dissolved South Bay Union and created separate K-12 unified school districts for the constituent cities.
[2] Manhattan Beach Unified School District and Redondo Beach Unified School District were formed as a result.
[5] Hermosa Beach City School District continued to serve Hermosa Beach for grades K-8, with residents able to choose between Redondo Union and Mira Costa high schools.