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Marine Corps Military Occupational Specialties -- What do they mean?

Updated: Nov 20, 2021

The Marine Corps has over 180,000 active-duty Marines, 60,000 Reserve Marines, and 14,000 civilian employees, providing myriad career opportunities in fields ranging from general soldiering such as infantry and armor, to skilled trades such as mechanics and utilities, and administrative roles including finance and supply operations. Every Marine earns a Military Occupational Specialty, or MOS, which is their day-to-day job while they are in the Marine Corps. Both Officers and Enlisted Marines will earn an MOS while in the Corps, and they can even have more than one. Today's blog will discuss some basics of what it means to have a Marine Corps MOS.

​It is important to note that unlike the other Armed Forces, the Marine Corps considers every Marine a Rifleman, and every Officer a Rifle Platoon Commander.  In other words, you will always have an MOS field you operate within, but the potential exists for every Marine to get called to the frontlines to fill the roles of provisional Infantry.  This mentality is reflected in how the Marine Corps trains all of its officers and enlisted, the emphasis on discipline and physical fitness, and the rugged fighting spirit shared by all Marines.

The Marine Corps breaks each functional occupation into a parent occupational field, such as Logistics, Intelligence, Finance, Infantry, or Engineering.  Each occupational field has a two-digit identifier. Each specific job, or occupational specialty, comes with two more digits after the occupational field that identify the MOS. Officer MOS's will typically have a zero in the last two digits (i.e. 1302, 0302, 0202), while enlisted MOS's will not (i.e. 3431, 0371, 1169). Though this is generally the case, there are some exceptions, specifically with aviation related MOSs.

Enlisted Marines can contract into a particular MOS field when they complete their contracting process with their recruiter and MEPS location. They will be assigned a Program Enlisted For code, or PEF code. Marines will ship to recruit training with a PEF code such as AE, CE, or HZ, and under each PEF code group is a set of MOSs which the recruit could be assigned. For example, the Infantry PEF code of UH includes the specialties of Rifleman, Machinegunner, Assaultman, and other MOSs, all under the umbrella of the UH Infantry PEF code. Prior to graduation, recruits will be informed by their Drill Instructors the specific MOS they will be assigned upon graduation. Another option for enlisted Marines is for poolees to enter the Marine Corps as an "open contract." This contracting occurs with the enlistee's recruiter, and the Marine will be provided a specific MOS at the completion of recruit training based on the manpower needs of the Marine Corps. 

Commissioned Officers have the ability to commission with Ground, Air, or Law Contracts through their commissioning source. Officers who are contracted into the Law or Aviation programs will attend OCS and TBS as normal and will matriculate into appropriate legal and aeronautical education pipelines. Ground Contract Officers will not receive their MOSs until they near graduation from TBS. These officers are provided a list of twenty-two MOSs which they can enter. They will rank these MOSs from most to least desirable, and they will provide this wish list to TBS staff. Utilizing student Officer academic rankings and the needs of the Corps, they will be assigned an MOS for continuing training after TBS.

To learn more about the difference between Enlisted and Officer career paths, visit our Officer & Enlisted Careers page.


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