What is the Infantry?

Infantry Marines are ground forces trained to locate and destroy the enemy by fire and maneuver or repel their assault by fire and close combat. The Marine Corps is an expeditionary force with the mission to fight and win battles for our Nation. Because the threats the United States faces are shifting and uncertain, the Marine Corps is strategically structured and organized to effectively fight in the air, on land and at sea. The infantry is the heart of this lethal fighting force. Of the hundreds of Military Occupational Specialties (Marine Corps term for jobs), the infantry (03XX) is the largest occupational field. All other occupational fields are structured to support the infantry with every Marine contributing to the fight.  

Marine Officers and Enlisted Marines: An Unbreakable bond


Infantry Marines must decisively defeat threats in the chaos of combat. This requires a close and trusting relationship between Marine Officers and the Enlisted Marines they lead. Infantry Officers (0302) are charged with upholding the discipline, morale and welfare of their unit. They lead attacks, offensive and defensive operations and other tactical missions. Enlisted Marines use their training and tactical mindset to execute these missions and win battles. No matter their role or rank, the bond between Marines is unbreakable.

What are Marine Corps Infantry Roles?

There are many Military Occupational Specialties required to accomplish the mission of Marine Corps ground forces. Contact a recruiter to learn more about infantry MOS.


  • Infantry Officer (0302)



  • Rifleman (0311)
  • LAV Crewman (0313)
  • Combat Rubber Reconnaissance Craft (0316)
  • Scout Sniper (0317)
  • Force Recon (0321)
  • Parachute Qualified Reconnaissance Man (0323)
  • Combatant Diver Qualified Reconnaissance Man (0324)
  • Parachute, and Combatant Diver Qualified Reconnaissance Man (0326)
  • Machine Gunner (0331)
  • Mortarman (0341)
  • Infantry Assaultman (0351)
  • Anti-Tank Missileman (0352)
  • Infantry Unit Leader (0369)
  • Marine Special Operations Command Critical Skills Operator (0372)


Training for Uncertain Threats


The Marine Corps is an expeditionary force, which requires its Marines to train for threats in any form. After earning the title Marine at Officer Candidates School or Marine Corps Recruit Training, Marines assigned an Infantry Military Occupational Specialty acquire skills for combat readiness.


After completing Officer Candidates School and The Basic School, Infantry Officers attend Infantry Officer Course (IOC) at Marine Corps Base Quantico, Virginia. Here they complete 15 weeks of training in crew-served weapons, patrolling and reconnaissance to qualify for any infantry platoon commander billet. Once they successfully complete IOC, these Marines are assigned to a unit in the operating forces.


After enlisted recruit training, Marines assigned an Infantry MOS attend the School of Infantry at either Camp Lejeune, North Carolina, or Camp Pendleton, California. During this 59-day course, they learn the Marine Corps warfighting philosophy, offensive and defensive operations, combat maneuvers, patrolling and fire and maneuver. Depending on their MOS, some Marines remain at SOI to complete the Infantry Weapons Course in one of three specializations: Infantry Machine Gunner, Infantry Mortarman or Infantry Anti-Tank Missile Gunner.

Adapting for Tomorrow’s Fight

Because the threats to our Nation are always changing, the Marine Corps must be ready to structure its forces for a competitive advantage.

In past conflicts, Scout Snipers (0317) enhanced the lethality of infantry battalions with long range precision fire on selected targets. In the face of evolving threats, the Marine Corps restructured its forces to house scout sniper platoons under reconnaissance battalions. Talk to a recruiter to learn more about the Reconnaissance Marine MOS (0321).

In 2021, the Marine Corps piloted the Infantry Marine Course, a limited experimental battalion to test training strategies to match the shifting threats Infantry Marines will face in future fights. Learnings will be considered for the infantry training program in the future.

Women have served faithfully in the Marine Corps for more than 100 years. In 2016, the Marine Corps opened ground combat roles to women. All Infantry Marines are trained to skillfully and faithfully execute their mission on the ground. Every Marine shares the same determination to fight until the battle is won.  

Requirements to Serve in the Infantry

Talk to a Recruiter to learn more about the general and physical requirements to serve as a United States Marine.