They are known as Sappers by many. In some foreign military units, you may hear the term Pioneer or Assault Pioneer used for someone who has this same job.
I am speaking of a Combat Engineer. These guys (and I believe it is now open to women) do a lot of the downright dirty work that seems often to go unnoticed, but provides safety and comfort to Army personnel.
In today’s post, I am going to examine the Army 12B MOS: Combat Engineer. I will provide a basic job description. I will tell you the Combat Engineer’s responsibilities and duties. I will also tell you the requirements to become a 12B Combat Engineer. Lastly, I will explain the training to become an Army 12B MOS.
Basic Job Description For The Army 12B Combat Engineer
When you put these 2 words together, you can get a good picture of the job of the Army 12B. He/she is first, and foremost trained in infantry fighting skills, because their MOS puts them in the heart of combat zones.
The engineer side of the title means they are normally in the position or erecting or tearing down. They provide their expertise in rough and dangerous terrain with areas like mobility, counter mobility, survival and general engineering. They work as a team to support combat operations as a whole.
Army 12B Combat Engineer’s Duties and Responsibilities
The Combat Engineer can be tasked with many various duties and responsibilities. The most important duty of all of them is to be completely combat proficient. The Army 12B is first an Infantry soldier because they are in the midst of combat situations. While the Combat Engineer will use various tools, their weapons are their #1 tools.
Other duties and responsibilities of the Army 12B Combat Engineer are:
Construct offensive fighting positions
Construct defensive positions
Construct both fixed and floating bridges
Create defensive obstacles
Place and detonate mines and explosives
Conduct route clearing operations
Mine detection
Prepare demolition explosives
Erecting communications installations
Build and maintain water filtration systems
Digging trenches and ditches
The Army 12B Combat Engineer’s duties and responsibilities can fall into many different categories. Often, this is a job that is not recognized as much as it should be. They build fortifications and tear them down to move and set them up again. It reminds me of digging a deep hole, burying an item in it, and being told to dig it up 2 hours later and repeat the process in a different location.
Requirements To Become An Army 12B Combat Engineer
The requirements to become an Army Combat Engineer are similar to the infantry MOS’s. They consist of:
A score of at least 87 on CO (combat operations) on the ASVAB
No security clearance is required
The Combat Engineer must have normal color vision
The physical profile under PULHES should be 111221 with the P being physical stamina, the U being upper extremities, the L being lower extremities, the H being hearing, the E being eyes and the S stands for psychiatric.
As long as you meet these requirements, you should have no problem attaining an Army 12B Combat Engineer MOS.
Training To Become An Army 12B Combat Engineer
The training for this Army MOS is a One Station Unit Training that lasts for 14 weeks. You will receive Basic Combat Training along with the Advanced Individual Training all in one. Some of this training will be in the field and some in a classroom setting.
From what I understand, the One Station Unit Training for the 12B MOS is held at Fort Leonard Wood, Missouri.
You will learn things such as:
Operating heavy equipment
Demolitions
Basic urban operations
Explosive hazards
Bridge building operations
Wire obstacle construction
and much more
You will also learn much just being on the job from those who have been doing it for a longer time.
Final Thoughts
Sappers, or Combat Engineers as they are formally known use a variety of tools and vehicles to perform their jobs. You will use hand tools such as hammers, chisels, screwdrivers, drills, measuring devices, etc… All items that a civilian general construction contractor may use.
But you may also be using bomb disposal robots, explosive devices, mine rollers, and other machinery like these that are not normally used by civilians.
When you leave the Army, it would be natural that any large or small construction operation would love to hire you with the Combat Engineer experience you will have.
We would love to hear from any former or current Army Combat Engineers. Please tell us what your job entailed and how it can help you in the civilian world. Feel free to share any experiences you had in this position while in a combat zone.
If you have comments, questions or any suggestions, please post them in the comment area below. Thank you for your service.
Other posts you may enjoy:
- Army 68W MOS Overview: Combat Medic
- Army MOS 25V: Combat Documentation/Production Specialist
- Army Combatives: What Every Soldier Should Know
- Combat Infantry Badge: 8 Things You Should Know

Chuck Holmes
Former Army Major (resigned)
Publisher, Part-Time-Commander.com
Email: mrchuckholmes@gmail.com
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Just a little correction here from a 12B, it isnt specificaly our job to build fixed and floating bridges, that would be a 12C (bridge crewmember)
Thanks for sharing, Bailey.