Petty Officer Third Class

Petty Officer Third Class is the fourth enlisted rank (E-4) of the UNSC Navy  and the lowest rank of non-commissioned officer or NCO. Directly above it is Petty Officer Second Class and directly below is Crewman. It is equal to the rank of Corporal in the UNSC Marine Corps, Corporal, and Specialist in the UNSC Army, Senior Airman in the UNSC Air Force.

Air Force

 * Airman Basic
 * Airman
 * Airman First Class
 * Senior Airman
 * Staff Sergeant
 * Technical Sergeant
 * Master Sergeant
 * Senior Master Sergeant
 * Chief Master Sergeant
 * Command Chief Master Sergeant
 * Chief Master Sergeant of Air Force

Army

 * Private
 * Private First Class
 * Specialist
 * Corporal
 * Sergeant
 * Staff Sergeant
 * Sergeant First Class
 * Master Sergeant
 * First Sergeant
 * Sergeant-Major
 * Command Sergeant-Major
 * Sergeant Major of the Army

Marine Corps

 * Private
 * Private First Class
 * Lance Corporal
 * Corporal
 * Sergeant
 * Staff Sergeant
 * Gunnery Sergeant
 * Master Sergeant
 * First Sergeant
 * Master Gunnery Sergeant
 * Sergeant-Major
 * Sergeant-Major of the Marine Corps

Navy

 * Crewman Recruit
 * Crewman Apprentice
 * Crewman
 * Petty Officer Third Class
 * Petty Officer Second Class
 * Petty Officer First Class
 * Chief Petty Officer
 * Senior Chief Petty Officer
 * Master Chief Petty Officer
 * Command Master Chief Petty Officer
 * Force Master Chief Petty Officer
 * Fleet Master Chief Petty Officer
 * Master Chief Petty Officer of the Navy