In the U.S. Coast Guard there, are nine ranks for enlisted personnel, designated from E-1 to E-9 as of 2015. Personnel with ranks of E-4 to E-9 are petty officers. There are 10 commissioned officer ranks, designated from O-1 to 0-10. Both enlisted and officer ranks have the same titles as U.S. Navy ranks. To see a list of ranks and military structure, visit the U.S. Coast Guard website at USCG.mil.
Officers holding the rank of ensign, O-1, through lieutenant commander, O-4, are junior officers. Commanders, O-5, and captains, O-6, are senior officers. Rear admirals, O-7, through admirals, O-10, are considered flag officers. The Commandant of the Coast Guard is the only person to hold the rank of admiral.
The Coast Guard has a separate rank structure for warrant officers. Warrant officers are considered specialist technical leaders. Qualified enlisted personnel with ranks from E-6 to E-9 and eight years of experience can seek appointment as warrant officers. There are nominally five ranks for warrant officers, but the ranks of warrant officer, WO-1, and chief warrant officer, CWO-5, are not in use by the Coast Guard as of 2015.
The Coast Guard does not have medical officers or chaplains of its own. Chaplains from the U.S. Navy and medical officers from the U.S. Public Health Service Commissioned Corps are assigned to the Coast Guard. These officers wear Coast Guard uniforms but replace the Coast Guard insignia with insignias from their own service.