The Pago Bay Japanese pillboxes are a pair of World War II-era coastal defense pillboxes located on the shore of Pago Bay, located on the central east coast of Guam. Built out of steel-reinforced concrete mixed with coral stone, these two structures were built by Japanese defenders during their occupation of the island between 1941 and 1944. They were listed on the National Register of Historic Places in 1991 as Pagu' Pillbox I and Pagu' Pillbox II. Neither of these would have seen substantial action during the 1944 liberation of Guam, whose military activities were focused on the western, central, and northern parts of the island.