Petty Officer Third Class - Definition and Overview

Petty Officer Third Class is the fourth enlisted rank in the U.S. Navy, just above Seaman and below Petty Officer Second Class, and is the lowest form of non-commissioned officer, equivalent to a Corporal in the U.S. Army, Marines or Airforce.

Unlike the Seaman and lower ranks, advancement to Petty Officer Third Class is not automatic given time in service, but is also contingent on performance evaluations by their superiors and rate examinations (test of speciality knowledge). The advancement cycle is currently every 6 months. Only a certain number of billets (job openings for this rank) open up biannually and all Seamen compete. The top scorers are chosen for advancement, but only in sufficient quantities to fill the billets available.

Royal Navy

In the British Royal Navy and navies of many other Commonwealth counties, the equivalent rank is Leading Rate, although this is considered junior to the nearest equivalent ranks of Corporal or Bombardier in the other military branches.

Related articles

• Petty Officer
• U.S. Navy enlisted rate insignia
• Comparative military ranks

U.S. military enlisted ranks
	E-1	E-2	E-3	E-4	E-5	E-6	E-7	E-8	E-9
Air Force:	AB	Amn	A1C	SRA	SSgt	TSgt	MSgt	SMSgt	CMSgt - CCM - CMSAF
Army:	PV1	PV2	PFC	SPC - CPL	SGT	SSG	SFC	MSG - 1SG	SGM - CSM - SMA
Marine Corps:	Pvt	PFC	LCpl	Cpl	Sgt	SSgt	GySgt	MSgt - 1st Sgt	MGySgt - SgtMaj - SMOMC
Navy:	SR	SA	SN	PO3	PO2	PO1	CPO	SCPO	MCPO - CMCPO - MCPON