Japan to Guam: No adapter needed
Your Japan plugs fit Guam's sockets directly -- no adapter needed for the shape. Voltage is compatible (100V vs 110V), so any dual-voltage or matching device is fine either way.
Your Japan plugs fit Guam's sockets directly -- no adapter needed for the shape. Voltage is compatible (100V vs 110V), so any dual-voltage or matching device is fine either way.