Best Co-op Mods for Single-Player Games: Play Skyrim, Elden Ring, Half-Life and More with Friends

The best co-op mods for single-player games — all in one place. Here you'll find mods that add multiplayer and cooperative play to games with no official co-op: from the iconic Elden Ring Seamless Co-op and Skyrim Together Reborn to classics like Half-Life Sven Co-op and Euro Truck Simulator 2 Coop Mod. All mods are tested and up to date in 2026.

Think of all the great single-player games you've spent hours — or entire days — playing. At some point, you've probably wondered: how would this game feel in co-op? Modders have been answering that question for years, and we've picked the best results. This list covers 17 games across multiple genres: shooters, RPGs, action games, strategy titles, and simulators. For more co-op fun, check out our best cooperative games list on the site.

Shooters gave modders some of the richest material to work with. Playing iconic single-player campaigns from Half-Life, DOOM, and Call of Duty in co-op feels completely different — every firefight demands coordination, and familiar levels reveal new angles. For more shooters and co-op titles, check out our best co-op games list.

Sven Co-op is a modification for Half-Life that adds full multiplayer support to the single-player campaign. It's been around long enough to feel like a standalone game, but at its core it's one massive mod. You'll find plenty of custom maps in various modes, including the ability to play through the entire Half-Life campaign. The mod is available on Steam and doesn't require the original Half-Life.

The co-op equivalent for Half-Life 2 and both its episodes. Synergy replaces Gordon's static player model with resistance fighter models and lets you take on the events of City 17 alongside friends. Beyond the campaign, the mod offers Team Play and Deathmatch modes where players take on the roles of the Combine and Rebels.

Synergy is available on Steam, but requires a license for Half-Life 2, Half-Life 2: Episode One, and Half-Life 2: Episode Two.

This mod for Call of Duty: Black Ops lets you play through the story campaign with a friend instead of going it alone. Co-op changes how missions feel: some sequences become easier, others suddenly demand real coordination. It's a great reason to revisit Black Ops in a whole new way.

Mars City Security adds co-op to Doom 3, along with several classic multiplayer modes on top of cooperative campaign play. Development on the original version stalled in 2015, but fans later took it upon themselves to continue — they committed to adding full co-op and improving the existing modes.

This mod for Crysis adds co-op by introducing AI into the game's multiplayer modes. Instead of standard PvP, players team up and fight against computer-controlled enemies. It's a solid option if you want to revisit Crysis without jumping into competitive online play.

NicksCoop is a fully functional co-op mod for Postal 2. It lets you play through the entire base game week and 2 additional levels. Players are well-synchronized, content isn't restricted, and other mods are supported. Multiplayer supports 2 to 16 players simultaneously.

RPGs are some of the best candidates for co-op mods: vast open worlds, branching quests, and tough bosses are all more rewarding with a friend. This section is home to the undisputed legend of the genre — Elden Ring Seamless Co-op, with over 10 million downloads.

One of the most downloaded game mods in history — over 10 million downloads on Nexus Mods. Seamless Co-op completely overhauls the cooperative system in Elden Ring: instead of summoning allies for individual boss fights, the mod lets you play through the entire game together from start to finish — including the Shadow of the Erdtree DLC — with up to 5 players. The mod was created by LukeYui, also known for his co-op mods for Dark Souls and Sekiro.

Deaths, checkpoints, and area transitions are all synchronized. Most popular mods are compatible. The 2025 version added support for the latest game patches.

Tactical Co-Op transforms XCOM 2 from a strictly single-player tactics game into a two-player co-op experience. Every turn becomes a discussion: who to push forward, when to use abilities, how to escape the next critical situation. It doesn't just make the game harder — it makes it far more tense and engaging.

Together Reborn is one of the most stable and actively maintained co-op mods for The Elder Scrolls V: Skyrim. It lets you play through the game with friends on a dedicated server, synchronizing quests, the world, and most in-game events — for up to 8 players. Compared to earlier attempts, this version runs noticeably more reliably and supports most popular mods, provided everyone uses the same load order.

The original Skyrim Together is the early version of the co-op mod — the one that started the whole idea of proper multiplayer in Skyrim. While Together Reborn has largely replaced it, some players still use the legacy version for compatibility with specific mod builds.

Fast-paced action games demand real teamwork in co-op — every enemy hits harder, every fight looks better. STALKER, DMC5, and Just Cause 3 become entirely different experiences with someone alongside you: missions that felt like routine suddenly fill with tactics and live reactions. Looking for more of the same? Check out our best co-op games for PC and consoles.

This mod for Devil May Cry 5 adds the option to play through the game together, despite the original being designed for solo play. Co-op feels especially dynamic here: fast fights, stylish combos, and relentless enemy pressure require genuine coordination. The familiar slasher becomes a more chaotic — and far more spectacular — shared adventure.

This mod adds full co-op to S.T.A.L.K.E.R.: Shadow of Chernobyl, letting you tackle both main and side quests together. The Zone remains just as dangerous — mutants, anomalies, and gunfights are all still there, but now you can face them as a team. Players can explore locations together, share gear and money, and coordinate through in-game chat.

The multiplayer mod for Just Cause 2 was a massive hit — so it's no surprise that the co-op release for Just Cause 3 was received just as warmly. JC3MP lets you connect to community servers running all kinds of modes, from races to full Roleplay. The mod is available on Steam and requires a licensed copy of Just Cause 3.

The Co-Op mod for Turok 2: Seeds of Evil lets you play through the full campaign with friends. It also includes a number of fixes and improvements, and works with the Steam remaster. One quirk: when a level ends, players need to manually type a console command to load the next map.

Strategy games and simulators gain a whole new dimension in co-op — sharing decisions with a friend in XCOM is something else entirely, and building a transport empire together in ETS2 or storming castles side by side in Mount & Blade is its own kind of pleasure.

Full Invasion is a popular mod for Mount & Blade: Warband that puts all players on one team against massive waves of enemies. There are dozens of scenarios inspired by Lord of the Rings, Star Wars, various historical conflicts, and much more. Years after its 2013 release, Full Invasion is still being updated.

Floris Evolved adds a large amount of new content to Warband, and most importantly — a co-op mode. While one player manages the campaign map, their teammates wait. When the player's party enters battle, a server spins up and friends join in, picking characters from the army roster. Players can even choose opposing sides. Everyone has access to the full party inventory.

Enjoy hauling cargo across Europe but getting tired of doing it alone? Bring some friends. This mod gives Euro Truck Simulator 2 full co-op support — whether you want to build a transport empire together or just race trucks through city centres, it's up to you.

Requires a copy of Euro Truck Simulator 2 on Steam, plus a free account on the mod's official website.

A co-op mod is a modification that adds an online multiplayer mode to a single-player game. Technically, it creates a local or dedicated server that other players connect to. Depending on the mod's complexity, it can synchronize character positions, quest progress, inventory, and in-game events. Some implementations — like Elden Ring Seamless Co-op — are polished enough to feel like an official feature.

It depends on the game. In titles with Easy Anti-Cheat or VAC, using client-side mods can result in a ban. However, most single-player games in this list — Half-Life 2, Skyrim, STALKER, Elden Ring — don't have aggressive anti-cheat systems for offline play. Elden Ring Seamless Co-op specifically disables FromSoftware's online services and runs in an isolated environment, which eliminates any ban risk.

It varies by mod. Most support 2–4 players. Skyrim Together Reborn supports up to 8, while Postal 2 NicksCoop supports up to 16. Elden Ring Seamless Co-op allows up to 5 players at once.

For most mods in this list — yes. Half-Life 2 Synergy, Just Cause 3 Multiplayer, and Euro Truck Simulator 2 Coop Mod all require a Steam license. The exception is Sven Co-op for Half-Life: it's distributed separately on Steam and doesn't require the original game.

Download the mod from Nexus Mods, install Mod Engine 2, place the mod files in your game folder, and launch through the mod's launcher rather than the standard shortcut. Full instructions are available on the mod's Nexus Mods page.

Usually yes, as long as all players have the same mod list in the same load order. Skyrim Together Reborn and Elden Ring Seamless Co-op are officially compatible with most popular mods. Mods that alter scripts or physics can sometimes cause desync — this needs to be tested on a case-by-case basis.

Co-op mods are just one way to play together. If you want a shared experience without manually installing mods, there are plenty of games with official co-op built in — supporting both LAN and online play out of the box. We've collected the best of them in a dedicated article: best co-op games for PC, PS4, PS5, Xbox, and Nintendo Switch.

Among them are plenty of open-world titles that are especially rewarding to explore together: Valheim, Deep Rock Galactic, It Takes Two, and more.

Which co-op mod is your favourite? Let us know in the comments!