Summary
Among specialized units under the Infantry inHearts of Iron 4, it’s perhaps theMarinesthat offer some of the more diverse gameplay options at a player’s disposal. Their natural training in amphibious settings makes them viable in engagements across rivers, marshes, and amphibious landings, making them rather versatile in more unique setups.
While the Marines inHearts of Iron 4only offer three (3) tiers of upgrades,Marine Divisionscomprised of different setups and even support elements such as Engineer Companies can transform them into even more specialized formations. However, for players who want to enjoy the full offerings of the Marines inHearts of Iron4, just how exactly should they set them up?
Updated on June 12, 2025, by Rhenn Taguiam:With the Trial of Allegiance DLC building upon South American nations in Hearts of Iron 4, fans of the historical grand strategy title might be curious as to how the likes of Chile, Brazil, and Argentina could rise to become superpowers of their own at the hands of HOI4 players. However, for fans curious about how they can best maneuver around the game’s rather complex combat mode, it might be time to learn about more specific types of unit arrangements - specifically the naval specialist Marines. As fans might notice, different Marine Templates are often fit for specific situations, with their skill towards naval and amphibious warfare potentially advantageous in the chaotic waters of South America. Players who want to master their usage of the Marines should consider using specific Templates that maximize these advantages, including those that specifically let them specialize in naval warfare or multiple terrains, as well as those that capitalize on Pioneers.
40
Support
Engineer, Logistics, Rangers, Support Anti-Tank, Support Anti-Air
Players who want to focus on hitting hard targets with their Marine Divisions should considerHard Marines, a 40-Width template focusing on 15 Marines assisted by four Anti-Tank units and two Artillery units. For Support, this Template relies on the traditional setup of Engineers, Logistics, and Rangers, with added Anti-Tank and Anti-Air to fight against heavier targets.
Theoretically, when aided by Engineer Companies, this template should give players a decent fighting chance on Marshes, Rivers, and amphibious landings. Its focus on Hard Attacks should make it effective against Tank and Mechanized Divisions, especially when players want to fight against larger armies.
27
Ranger, Logistics, Engineers, Signal, Support Anti-Air
Building a 27-Width Marine Division facilitates more efficient coastal invasions, making this the perfect setup forNaval Dominance. Combining this Division Template with Artillery gives the Division better firepower, while a standard Engineer Company should provide it with much-needed Terrain bonuses for maximum performancein the World War 2 game.
The trade-off for this setup would be a weaker Organization on the part of the Marines, which means they can’t push territories for as long unless they have reinforcements. While it’s possible to use Force Attack to avoid this setback, it’s ideal to also equip this Division with a Signal Company so they can de-organize weaker enemy Divisions much faster as well.
34
Ranger, Engineer, Support Anti-Air
Given how Plains and Urban fights are likely the more common Terrain types where players will find themselves engaged in naval battles, it makes sense for theirMulti-Terrain Marinesto be set up in such a way that makes these fights feasibleinHearts of Iron 4gameplay.
An 11-Marine set up alongside an Engineer Company should provide a decent enough base to build upon with additional Ranger and Support Anti-Air Companies and a 4-stack Artillery accompaniment. The resulting stats should give this Division a high Soft Attack and excellent Defense, allowing them to outlast opponents in these skirmishes and provide enough time to bolster their forces with reinforcements.
25
Pioneers, Rangers, Medium Flame Tank, Support Artillery
By the time players unlock new Special Forces Doctrines via theArms Against TyrannyDLC, focusing on the Marines Tree will unlock Pioneers - essentially Marine-specializing substitutes for Engineers. Progression dictates the focus of these Pioneers, whether they improve performance in Jungle or Amphibious Terrain, or boost Amphibious Armor or Line Artillery. When placed in a 25-Width template like thePioneering Marines, they can drastically improve the overall Defense and Breakthrough of the entire unit.
In thisparticularHearts of Iron 4setup, the Pioneering Marines can enjoy bonuses to overall Attack, Defense, and Movement across Marshes, Jungles, Rivers, and Amphibious Terrains. Not only that, but all Marines and Amphibious Armor get additional breakthrough, making them more viable for hard-hitting semi-naval warfare.
45
Engineers, Anti-Air, Logistics, Artillery, Signal
Fans who want to upgrade theirwarfare methodswith Marines could consider mixing and matching via theMixed Rolestemplate. This starts with six (6) Marines and expands into 10 Infantry, with four (4) Artillery and one Anti-Air for backup, forming a Combat Width 45 setup. This should provide players with ample firepower to accommodate different angles, while their Support Companies supplement them with attack bonuses.
By the time players get more specialized upgrades, they can replace Infantry with Mountaineers to accommodate a more diversified kit. This should theoretically allow players to begin a more aggressive frontline approach while leaving enough room to receive backup from smaller Combat Width 15 to 18 or even larger Combat Width 20 setups.
30
Engineer, Artillery, Anti-Air, Recon, Medium Flame Tank
While unlocking Marines can provide players with more specialized firepower in theirHearts of Iron 4experience, they may be able to capitalize on their potential even further once players unlockthe Amtrac in the World War 2 sim. In this Amtrac Marine Balance template, players can tinker with a Combat Width 30 setup to accommodate most Terrain types with manageable attack penalties in Urban, Jungle, and Forest settings.
However, despite these attack penalties, the main priority of this 6/9 Build is to supplement the base strength of Marines with the more balanced firepower of the Amtrac upgrade. Their more solid defense, especially when assisted by Artillery and Engineer Support Companies, should help players provide additional firepower regardless if they’re pursuing aggressive plays or defensive pursuits.
20
Engineer, Artillery, Anti-Air, Field Hospital, Flame Tank
Players who want an alternative take onthe flexible army in theirHearts of Iron 4gameplayshould consider going for theStrategic Marine Assaulttemplate. This particular Combat Width 20 setup takes advantage of the multi-terrain perks of smaller numbers, even with the slight penalties for the presence of an Amtrac Battalion.
This setup aims to highlight the capabilities of the Marines to accommodate not just amphibious warfare but also multi-directional attacks. Instead of having one large Marine division pushing into enemy territory, this template encourages positioning them into many chokepoints. When aiming for a theoretical port, this means stationing one head-on and then deploying two more on either side to secure the flank. The flexibility of this template’s Combat Width also has room to place other Support Companies like the Field Hospital or Logistics Company for additional support.
24
Engineer, Anti-Air, Anti-Tank, Recon, Medium Flame Tank
Players who want to use their Marines formore standardHearts of Iron 4playsshould consider a more traditionalStandard Marine Artillerysetup. This Combat Width 24 template emphasizes a 9/2 composition with Marines and Artillery at the forefront, suffering some penalties in Forests and Jungles but with quite a lot of boosts in terms of defense.
This build is a more traditional take on the Marine template, with Anti-Air Support Companies specifically focusing on Armor and Piercing to secure both offense and defense. While not the most powerful template in terms of sheer firepower, their innate bonuses could be enough to push multi-directional assaults with opportunities to flank and plug defenses.
18
Engineer, Artillery, Recon, Medium Flame Tank
Players who want a more flexible take on their Marine templates intheirHearts of Iron 4playthroughshould consider tryingAll-Rounder Marines. This Combat Width 18 template aims to follow through attacks with nine (9) Marine Battalions, relying heavily on Support Engineers and Artillery for bonuses on Naval Attack and Soft Attack while specializing further with Recon and Medium Flame Tanks.
Theoretically, Combat Width 18 should be able to help Marines accommodate most Terrain types. This should let them support other divisions from the backlines or become more forward units.
Engineer, Artillery, Anti-Air, Signal, Light Flame Tank
Players who want toexperiment with their Marine setupsshould consider trying theEarly-Game Play Safesetup. This Combat Width 30 9/4 build incentivizes giving players access to multiple divisions in the early parts of the game, enabling them to cement their frontlines on the offense or fill defensive gaps when receiving push-back.
While not necessarily the strongest deployment of Marines, the all-around nature of this setup allows players to use this as a branching-off point when expanding their builds to accommodate certain combat situations. This way, players don’t get as punished in the early game when their experiments go wrong, as it’s easy to revert to a more manageable division template.
