St. John's School is an international college preparatory school located in the Tumon area of Tamuning, Guam, United States. The school, affiliated with the Episcopal Church in Micronesia, serves students from pre-kindergarten through 12th grade. The school is accredited by the Western Association of Schools and Colleges and authorized by the Internatio…St. John's School is an international college preparatory school located in the Tumon area of Tamuning, Guam, United States. The school, affiliated with the Episcopal Church in Micronesia, serves students from pre-kindergarten through 12th grade. The school is accredited by the Western Association of Schools and Colleges and authorized by the International Baccalaureate Organisation to provide the IBO Diploma.