Ships Companies Ports Documents Distances FAQ Contacts Guam Time: GMT +10. International dialling code: +671. Territorial waters: Territorial limits of 12nm are claimed with a contiguous zone (CZ) of 12nm and exclusive economic zone of 200nm. Capital city: Agana. PORT LATITUDE LONGITUDE REMARK UNCTAD TIME ZONE MAX DRAFT MAIN PORT DETAILS Apra Harbour 13° 27.0' N 144° 37.0' E Port Open GUAPR GMT +10 16.20   Details Apra Harbour 13° 27.0' N 144° 37.0' E Port Open GUAPR GMT +10 16.20   Details