What Is Military Occupational Speciality (MOS)?

Important Note: When you buy through our links, we may earn a commission. As an Amazon Associate we earn from qualifying purchases. Content, pricing, offers and availability are subject to change at any time - more info.

Hundreds of jobs are available to new U.S. Army or Marine Corps recruits depending on their skill set, talent, training, and experience. How do the Army and Marine Corp break down these career fields and assign them to individuals? By Military Occupation Speciality. Let’s find out what exactly that is.

Military Occupation Specialty (MOS) is a job or position available in the military for all of its service members. Hundreds of MOSs are available depending on skill, experience, and training. A MOS code is a unique alphanumeric code that will be assigned to it both in the Army and Marine Corps.

This article will detail what MOS is based on the U.S Army and The U.S Marine Corps. It will dive into all the branches, divisions, categories, subcategories, and more, giving you a complete insight into how the military goes about assigning positions.

What Is A Military Occupational Specialty (MOS)?

MOS stands for Military Occupational Specialty if you don’t already know. A military occupational specialty is a specific job (career field) that is assigned to members of the United States Amy and the United States Marine Corps. Each job is associated with a four or three-character code, typically referred to as the MOS code.

Additionally, the Army and the Marine Corps have their own unique MOS codes because these branches of the military are separate from one another.

Take note that the United States Air Force and Navy do not use a MOS code to identify the particular fields that individuals are placed in. The Air Force uses AFSC (Air Force Specialty Codes), and the Navy uses designators and ratings in correlation with the NEC (Navy Enlisted Classification System).

How Are Moss Assigned?

MOSs are typically assigned based on an individual’s skills, talents, and personal traits. They are also allocated via available job openings or Billets. MOSs may, in some situations, be assigned to those who enlist via a combination of experience and/or training.

Marine Corps MOS

The Marine Corps separates their jobs into fields known as “occupational Fields” (OccFld). These fields have no distinction between marines and officers and are broken down into three types.

What Are The Three Types Of Moss For The Marine Corps?

The three types of MOSs in the Marine Corps are namely;

  • Occupational Fields (1-79)
  • Miscellaneous Requirement Occuptaitional Fields (80XX)
  • Reporting Occupational Fields (90XX)

These MOSs can be further subdivided into primary and non-primary MOSs. Take note that primary MOSs can be further categorized into primary, basic, or additional. Non-primary MOSs can be classified as free, necessary, or exception.

Here is a list of the occupational fields covered by the three categories of MOSs in the United States Marine Corps.

Primary and non-primary Marine Corps MOSs

Below are each of the three broken down categories for primary and non-primary Marine Cops MOSs.

Basic MOS

This MOS applies to new marine recruits or individuals who are not explicitly qualified in any skills or have had training. Additionally, suppose an R.C. (Reserve Component) Marine transfers to another unit, and they have not obtained the correct MOS that is required to fulfill the Billet they were assigned to. In that case, they will be given a basic MOS.

Primary MOS (PMOS)

This MOS is the initial indicator relating to a Marine’s knowledge and skill. PMOSs have the option and ability to get promoted. Promotions are only available to;

  • Enlisted Marines
  • Warrant Officers
  • Chief Warrant Officers
  • Limited Duty Officers

Take note that promotions given to enlisted Marines will be based on their basic MOS and never an AMOS.

Additional MOS (AMOS)

This is basically a PMOS that is awarded to a Marine that already had the title of PMOS. This implies “Extra” for the Marine that has already gotten primary MOS. This typically happens when a Marine takes a lateral move into a new position (job). Take note that promotion in this MOS category is not possible.

Necessary MOS (NMOS)

This MOS is a prerequisite MOS and is only available to Marines that obtained the corresponding primary MOS. This MOS denotes a Marines’ particular skill or training which is in addition to their PMOS.


This type of MOS deals with skills that are not related to a Marine’s primary skill. Moreover, this MOS can be obtained no matter the Marine’s PMOS.

Exception MOS (EMOS)

This MOS is typically labeled as a free MOS; however, it has a few exceptions that require a primary MOS.

Are There Any Other Moss In The Marine Corps?

There are two additional types of MOSs for the Marine Corps that are special MOSs which are namely, Reporting MOSs and Billet Designators.

Reporting MOS

Thes MOSs are assigned in the 90XX field; however, they are not found as a requirement to fill a billet on a USMC T/O.

Billet Mos (BMOS)

This is usually a PMOS but can also be an NMOS, FMOS, EMOS, or even a Billet Designator. This particular MOS will be listed on the USMC T/Os for each Billet.

United States Army MOS

As with the Marine Corps, the U.S. Army has its own coding system when it comes to MOS. New recruits can expect around 190 MOS options compared to the Marines’ 90 occupational fields. The MOS options can be broadly categorized into fields that include;

  • Infantry branch
  • Cyber operations
  • Military intelligence
  • Administration
  • Logistics

These can be further divided into the categories below;

  • Native Language Speaker
  • Infantry
  • Core of Engineers
  • Field Artillery
  • Air Defence Artillery
  • Aviation
  • Cyber Operations Specialists
  • Special Forces
  • Armor
  • Signal Corps
  • Judge Advocate General’s Core
  • Electronic Warfare
  • Military Police (M.P.s)
  • Military Intelligence
  • Financial Management
  • Psychological operations
  • Civil Affairs
  • Public Affairs
  • Army Acquisition Troops
  • Chaplain
  • Medical CMF
  • Chemical
  • Recruiting and Retention
  • Transportation
  • Ammunition
  • Mechanics and Equipment
  • Quartermaster Corps
  • Combat Electronic Systems

For a full list of the MOS branches and their fields, you can have a look at this list here.

Although going over each individual branch for each of these subcategories is beyond the scope of this article, we will outline and detail the main categories.

Infantry Branch

Infantry will work to defend their country from threats. This will include capturing, deterring, and destroying the enemy. The infantry MOS comprises of approximately 11 categories.

It also includes assisting in reconnaissance with the addition of helping to mobilize troops and weaponry that will support the mission.

The infantry branch will include divisions of the field artillery soldiers, special forces, air defense and aviation, armor, ammunition and signal corps.

Cyber Operations

Cyber operations consist of about 46 MOSs that will include electronic warfare. Cyber operations include operating and aggressively defending the Department of Defence’s information network. It will also entail cyberspace effects in the form of offensive and defensive strategic elements that will be used on global adversaries.

Lastly, it will also develop and deploy capabilities in cyberspace to help equip the U.S Army for the future against any adaptive adversaries.

Military Intelligence

This is the U.S Army’s intelligence branch, and its primary mission is to provide timely, relevant, synchronized, and very accurate intelligence in addition to electronic warfare support. This information is provided to operational, tactical, and strategic level commanders who will use it as they see fit to advance a mission further.

The military intelligence branch comprises of approximately 35 MOSs.


Administration deals with civil and public affairs, financial management, recruiting, and judge advocate General’s core.

The MOS’s in this field are communicators, planners, coordinators, paralegal specialists, judges, and accountants.

As you can imagine, all the day-to-day aspects that it takes to run the U.S Army are predicated on the individuals that are under the umbrella of the Administration MOSs.


You will find these transportation specialists anywhere between sea, land, and air. These specialists operate and repair all transportation vehicles in the U.S. Army.

Some operators include cargo specialists, watercraft operators, railway equipment operators, tank systems maintainers, and utility equipment repairers.

This branch includes Mechanics and Equipment Maintenance and Combat Electronic Systems Repair and Maintenance.

Summarizing What MOS Is In The United States Army And Marine Corps

As we now know, MOS is a field career in the United States Army and Marine Corps that is signified by an alphanumeric code. Each code is unique and represents a specific branch or field that the member of the Army or Corps is in.

Hundreds of MOSs can be broken up into categories and subcategories for the career paths in both the Army and Marine Corps. If you are looking to join either branch, then it would be in your best interest to figure out which branch would best suit your specific skill set and speak to a recruiter about it.

Similar Posts