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The Main Differences Between the Army and the Marines

The Main Differences Between the Army and the Marines

Unless you’re very fond of the military, there’s a good chance that if you’re not in a branch, you may not know the exact differences between each of the services. Especially comparable services or branches such as the Army and the Marines.

Many people are quite surprised to find out that differences between branches stem not only from the duties and training that occur, but also the equipment used, the commands, and the entire organization.

Army soldiers in their uniform and gear posing for a photo

While we could compare and contrast every branch of the military (for those of you who don’t know, there are 6 in total), today we’re just going to be focusing on the differences between the Army and the Marines. So, if you’ve wanted to learn more or get an inside look at how certain branches differ from one another, than just keep reading.

Breaking Down the Basics of the Army

Before we dive into the five key differences of the Army compared to the Marines, the first thing we want to cover is the basics of each branch. That way, everyone will have a good understanding as to what each branch of service does and how they are structured, which leads to why these differences are present.

So, who, or what, is the United States Army? Well, this branch is known as the land warfare branch of the Military and has been around since the origins, which began around the time of the Revolutionary War. Even though this branch was in service for quite some time, it wasn’t until 1784 that the “Army” was first recognized.

The US Army is actually the biggest military branch as there are over 476,000 active-duty personnel enrolled. This number doesn’t even include the Army National Guard, which includes about 343,000 members and the Army Reserve which adds another 200,000.

Army soldiers standing at attention

These active-duty members are responsible to cover and man the main ground force for the country, making their primary objective and mission to always protect and defend the USA. Though this objective may sound a little destructive or aggressive, the Army is used to primarily protect the peace and the security of the United States and its people. Hence why its mission is: “to fight and win our Nation’s wars by providing promote, sustained land dominance across the full range of military operations and the spectrum of conflict.” 

What Does the Army Do?

When it comes to wars, missions, and keeping the peace, the Army acts as the initial land branch of the Armed Forces, taking care and protecting the country (internationally as well as domestically) on land.

The responsibilities can include supporting national policies and implementing national objectives, as well as preserving the peace and security of the country and overcoming any nations that implement aggressive acts that put the peace and security of the nation as risk.

Breaking Down the Basics of the Marines

Taking a look at the United States Marine Corps, it is important to note that their responsibility differs, right off the bat. Their main mission and responsibility are to conduct expeditionary and amphibious operations. The Marines also operate alongside the Navy, primarily, however that doesn’t mean that they won’t come into contact and work alongside the Army and the Air Force as well. While the Marine Corps is technically its own branch, it has been operating under the US Navy since 1834.

Marine soldiers standing in lines at attention

The Army may be one of the biggest branches to date, however the Marine Corps is actually the smallest compared to the big four (which includes the Air Force, Navy, Army and of course the United States Marine Corps [USMC]). To put it into perspective, the USMC has 182,000 active-duty personnel, along with 38,500 Marine Reserves.

What Does the Marine Corps Do?

The Marines act as a defense of advanced naval bases, hence why they work so closely with and are underneath the Navy, helping to support naval campaigns and other campaigns that may extend to any other Armed Forces branches.

While the Marines are ready and able to support all branches, there is a selective group that consists of elite Marines. These active-duty individuals have been trained and prepared for combat that falls on any terrain or in any situation. It’s important to note that Marines have been involved in every major US conflict, standing to protect their country.

There are many responsibilities of the Marines, however their three main duties or objectives are; defense of advanced naval bases and supporting naval campaigns, development of tactics and equipment used by land forces (Army and Air Force), and any other duty that may be issued by the President or Department of Defense.

The Key Differences Between the Army and the Marine Corps

Now that we have a clear understanding of the purpose and overview of each branch, it’s time to break down the 5 key differences between the two. Some of these may be obvious whereas others may be somewhat surprising. Let’s get started!

 1. Responsibilities

So, we have covered that the Army is responsible for protecting and instilling peace on the land, meaning that they cover and operate on land-based missions only. However, the Marine Corps, though a branch of the Navy, are called to handle “amphibious” operations. This means that the terrain, environment, and location does not matter. If the operation is at land or out on water, the USMC have to be prepared and able to handle it.

Now both branches have the same goal at the end of the day; to protect and preserve the peace and security of the Nation. It’s just in the operations and places in which this act is carried out that truly differs.

Army soldier standing at attention in front of a US flag

The Army will work to support national policies, help to implement any objectives and will overcome any nations that seem aggressive or indifferent towards the US. The Marines are the ones who will assault, capture and control anyone to reach enemy forces. They also have a warfare speciality, in case needed.

 2. Command

This difference should not come as a surprise. While the Army is older, technically, the Marines have origins from the American Revolutionary War, and the Army is its own branch whereas the Marines operate under the Navy.

In terms of their squads, the Army platoons have smaller squads, with a leader in charge of a 4-man fire team, whereas the Marines have a sergeant who leads three fire teams.

Though, in terms of command, there are many similarities between the two:

  • Both branches rely on company and battalion commanders for orders
  • Both branches get organized into larger companies with subordinate squads

 3. Eligibility

Training is a whole other ball game when it comes to these two branches, or even branches in general. However, to simplify the differences, for this section we’re only looking at who is eligible to join either the Army or the Marines.

Army soldiers in training running

So, for the Army, members between the ages of 17 – 35 can be enlisted, however if anyone is under the age of 18, they will need parental consent. You also must be a legal permanent resident of the United States.

The Marines allows members to join as early as 17, however the maximum age for this branch is 29 years.

For both branches, all new recruits must complete the Armed Services Vocational Aptitude Battery, also known as the ASVAB.

In terms of simplistic differences between the training components, the Army’s Basic Combat Training lasts 10 weeks and the Marine Corps Basic Training lasts 13.

4. Weapons

Given that both branches fight on different terrain and environments, it may come as no surprise that the weapons issued to Army soldiers and the Marines are different. Let’s break this down further.

The Army is usually the first branch to receive any new forms of weapons, for example, these soldiers have the M4 way before the Marine Corps made the transition. The same goes for communication and add on gear, such as hand grips and lasers.

The Army relies mostly on the AT-4, SMAW, and Javelins whereas the Marines primarily use the SMAW. In addition, the Army prefers and uses the M320 as its grenade launcher, but the Marines use the M203.

Marine soldier with a M320 grenade launcher

For more information on issued gear and weapons, check out one of our most recent blog posts on Army Issued Gear here.

Now both teams have fire support on the battlefield, but their artillery and close air support differs. The Marines will utilize artillery, air, and naval assets for fire support,

5. Promotions

And at last, we’ve reached the final main difference that we will be covering in this blog post, and this is promotions or rather, opportunities for career advancements between the two branches.

Since the Marines do not have their own doctors or dentists (these occupations are used from the Navy), there are more opportunities in the US Army than there are in the Marines, especially when it comes to Military Occupational Specialties.

However, both branches do have the option for the soldiers to join special forces. Marines who excel in the standard infantry can compete for a prized spot on Force RECON, and Army personnel who excel may advance to the airborne unit.

Marines special unit going into a warehouse in their combat gear with weapons


While these are not all of the differences between the Army and the Marines, it does cover some of the bigger, main differences between the two. So, knowing all of these, we want to ask, which branch would you rather join and be a part of? The Army or the Marines?

For more information, check out some of our other blogs by visiting the link here and be check out our shop for military, hunting, and backpacking gear from the brands you know and love. 

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