Bishop Garcia Diego High School is also accredited by the Western Association of Schools and Colleges
. WASC is one of six regional accrediting associations in the United States. The Commission provides assistance to schools located in California, Hawaii, Guam, the Commonwealth of the Northern Marianas, American Samoa, the Federated States of Micronesia, the Republic of the Marshall Islands, and East Asia. The Accrediting Commission for Schools is composed of twenty-six representatives from educational organizations. The school has received full accreditation terms in 2022, 2014, 2008, 2002, 1996, 1990, 1984 and 1978.