The Colegio San Agustin-Binan formally opened its doors to secondary education on its third year of operation in the academic year 1987-1988. Government recognition was granted to the High School Department on January 4, 1989. By the academic year 1989-1990, with all years completed and the public trust gained, the department has consistently maintained a population doubling each year.
Academic and non-academic honors and awards received by the school for the past academic years had continually motivated the Junior High School department to soar greater heights by bettering its services, improving its facilities, strengthening its faculty, and regularly reviewing its curricular offerings, thus with its avowed thrust of excellence, it took bigger steps by voluntarily submitting itself to PAASCU accreditation. On November 11-12, 1999, the preliminary visit was slated. On April 3, 2000, the Department received with joy the news of a successful survey and was given a Level I status for a year. The year after, the formal survey visit was made in October 11-12, 2001 and the Department was granted a Level II status for three years by the Federation of Accrediting Agencies of the Philippines (FAAP). The first resurvey visit took place last October 6-7, 2005 and on May 5, 2006, the Department received the certificate of accreditation from the Philippine Accrediting Association of Schools, Colleges and Universities (PAASCU) with Level II status for five years. Just recently, the second resurvey visit happened last October 20-21, 2011 which resulted to another five-year reaccreditation Level II status.