Free Online Co-Op Games on Steam
Steam currently has 7,543 Online Co-Op games available to download and play. Explore our list of the best free games ranked by popularity and ratings. Data for this list is calculated from reviews and player counts reported directly by Steam and will be updated in real-time. Free Online Co-Op game rankings were last updated on 8/7/2025.
Looking for more? Explore other lists such as:
- Best online co-op games on Steam
- Best online co-op Steam Deck games
- Best online co-op Steam games for Mac OS
- Best online co-op Linux games on Steam
- Free Steam games
- Most played Steam games
- Best rated Steam games
1. Counter-Strike 2
For over two decades, Counter-Strike has offered an elite competitive experience, one shaped by millions of players from across the globe. And now the next chapter in the CS story is about to begin. This is Counter-Strike 2.
Counter-Strike 2 holds the #1 spot for "best free Online Co-Op game on Steam" with a Player Score of 86. Its score was calculated by analyzing a total of 8,938,039 reviews on Steam. This breaks down to a total of 7,731,604 positive reviews and 1,206,435 negative reviews — making it "Very Positive" on Steam.
It can be played and ran on both Windows and Linux systems. At the moment, it is possible to play Counter-Strike 2 on the Steam Deck (though some functionality may be limited).
2. Dota 2
Every day, millions of players worldwide enter battle as one of over a hundred Dota heroes. And no matter if it's their 10th hour of play or 1,000th, there's always something new to discover. With regular updates that ensure a constant evolution of gameplay, features, and heroes, Dota 2 has taken on a life of its own.
Dota 2 has achieved a Player Score of 81, placing it in the #2 spot for the best free Online Co-Op games. Its score was calculated by analyzing a total of 2,533,468 reviews on Steam. This breaks down to a total of 2,063,292 positive reviews and 470,176 negative reviews — making it "Very Positive" on Steam.
It can be played and ran on Windows, Mac, and Linux systems. At the moment, it is possible to play Dota 2 on the Steam Deck (though some functionality may be limited).
3. PUBG: BATTLEGROUNDS
PUBG: BATTLEGROUNDS, the high-stakes winner-take-all shooter that started the Battle Royale craze, is free-to-play! Drop into diverse maps, loot unique weapons and supplies, and survive in an ever-shrinking zone where every turn could be your last.
PUBG: BATTLEGROUNDS has achieved a Player Score of 59, placing it in the #3 spot for the best free Online Co-Op games. Its score was calculated by analyzing a total of 2,587,566 reviews on Steam. This breaks down to a total of 1,540,773 positive reviews and 1,046,793 negative reviews — making it "Mixed" on Steam.
It can be played and ran on Windows systems. At the moment, it is not possible to play or run PUBG: BATTLEGROUNDS on the Steam Deck.
| Release Date | 12/21/2017 |
| Franchise | KRAFTON, Inc. |
| Developers | |
| Publisher | KRAFTON, Inc. |
| Steam App Id | 578080 |
4. Delta Force
Delta Force, a free-to-play 1st-person tactical shooter, returns as the latest in the classic series. With 25 years defining the genre, Delta Force is back with an upgraded arsenal of weaponry, jaw-dropping environments, and a truly dynamic world.
Delta Force has achieved a Player Score of 61, placing it in the #4 spot for the best free Online Co-Op games. Its score was calculated by analyzing a total of 128,670 reviews on Steam. This breaks down to a total of 79,414 positive reviews and 49,256 negative reviews — making it "Mixed" on Steam.
It can be played and ran on Windows systems. At the moment, it is not possible to play or run Delta Force on the Steam Deck.
| Release Date | 12/4/2024 |
| Developers | |
| Publisher | TiMi Studio Group |
| Steam App Id | 2507950 |
5. Marvel Rivals
Marvel Rivals is a Super Hero Team-Based PVP Shooter! Assemble an all-star Marvel squad, devise countless strategies by combining powers to form unique Team-Up skills and fight in destructible, ever-changing battlefields across the continually evolving Marvel universe!
Marvel Rivals has achieved a Player Score of 78, placing it in the #5 spot for the best free Online Co-Op games. Its score was calculated by analyzing a total of 306,677 reviews on Steam. This breaks down to a total of 239,699 positive reviews and 66,978 negative reviews — making it "Mostly Positive" on Steam.
It can be played and ran on Windows systems. At the moment, it is possible to play Marvel Rivals on the Steam Deck (though some functionality may be limited).
| Release Date | 12/6/2024 |
| Developer | NetEase Games |
| Publisher | NetEase Games |
| Steam App Id | 2767030 |
6. Warframe
Awaken as an unstoppable warrior and battle alongside your friends in this story-driven free-to-play online action game
Warframe has achieved a Player Score of 87, placing it in the #6 spot for the best free Online Co-Op games. Its score was calculated by analyzing a total of 626,797 reviews on Steam. This breaks down to a total of 548,189 positive reviews and 78,608 negative reviews — making it "Very Positive" on Steam.
It can be played and ran on Windows systems. Valve has also verified it as playable on the Steam Deck and will run well.
| Release Date | 3/25/2013 |
| Developer | Digital Extremes |
| Publisher | Digital Extremes |
| Steam App Id | 230410 |
7. Tom Clancy's Rainbow Six® Siege X
Rainbow Six Siege X is the reference in tactical team shooters, where elite strategy and execution triumph. Enjoy free access to Quick Match, Unranked and Dual Front game modes with a selection of operators.
Tom Clancy's Rainbow Six® Siege X has achieved a Player Score of 83, placing it in the #7 spot for the best free Online Co-Op games. Its score was calculated by analyzing a total of 1,432,482 reviews on Steam. This breaks down to a total of 1,191,626 positive reviews and 240,856 negative reviews — making it "Very Positive" on Steam.
It can be played and ran on Windows systems. At the moment, it is not possible to play or run Tom Clancy's Rainbow Six® Siege X on the Steam Deck.
| Release Date | 12/1/2015 |
| Developer | Ubisoft Montreal |
| Publisher | Ubisoft |
| Steam App Id | 359550 |
8. tModLoader
Dig, Fight, and Build your way through the world of player-created mods on Terraria with tModLoader - this DLC makes modding Terraria a reality!
tModLoader has achieved a Player Score of 96, placing it in the #8 spot for the best free Online Co-Op games. Its score was calculated by analyzing a total of 323,219 reviews on Steam. This breaks down to a total of 313,844 positive reviews and 9,375 negative reviews — making it "Overwhelmingly Positive" on Steam.
It can be played and ran on Windows, Mac, and Linux systems. At the moment, it is possible to play tModLoader on the Steam Deck (though some functionality may be limited).
9. Team Fortress 2
Nine distinct classes provide a broad range of tactical abilities and personalities. Constantly updated with new game modes, maps, equipment and, most importantly, hats!
Team Fortress 2 has achieved a Player Score of 90, placing it in the #9 spot for the best free Online Co-Op games. Its score was calculated by analyzing a total of 1,172,778 reviews on Steam. This breaks down to a total of 1,057,532 positive reviews and 115,246 negative reviews — making it "Very Positive" on Steam.
It can be played and ran on both Windows and Linux systems. At the moment, it is possible to play Team Fortress 2 on the Steam Deck (though some functionality may be limited).
10. Once Human
Once Human is a multiplayer open-world survival game set in a strange, post-apocalyptic future. Unite with friends to fight monstrous enemies, uncover secret plots, compete for resources, and build your own territory. Once, you were merely human. Now, you have the power to remake the world.
Once Human has achieved a Player Score of 74, placing it in the #10 spot for the best free Online Co-Op games. Its score was calculated by analyzing a total of 140,246 reviews on Steam. This breaks down to a total of 105,233 positive reviews and 35,013 negative reviews — making it "Mostly Positive" on Steam.
It can be played and ran on Windows systems. At the moment, it is not possible to play or run Once Human on the Steam Deck.
| Release Date | 7/9/2024 |
| Developer | Starry Studio |
| Publisher | Starry Studio |
| Steam App Id | 2139460 |
More Free Online Co-Op Games
Explore even more rankings for the 100 best free Online Co-Op games available on Steam.
| Image | Name | Actions | ||||
|---|---|---|---|---|---|---|
| 857,993 | 8/21/2012 | 86 | Free | Steam Charts | |
| 421,412 | 7/9/2013 | 81 | Free | Steam Charts | |
| 294,345 | 12/21/2017 | 59 | Free | Steam Charts | |
| 112,064 | 12/4/2024 | 61 | Free | Steam Charts | |
| 43,560 | 12/6/2024 | 78 | Free | Steam Charts | |
| 37,400 | 3/25/2013 | 87 | Free | Steam Charts | |
| 37,093 | 12/1/2015 | 83 | Free | Steam Charts | |
| 30,577 | 5/16/2020 | 96 | Free | Steam Charts | |
| 28,402 | 10/10/2007 | 90 | Free | Steam Charts | |
| 19,635 | 7/9/2024 | 74 | Free | Steam Charts | |
 | 15,190 | 10/23/2013 | 88 | Free | Steam Charts | |
 | 13,747 | 8/10/2023 | 25 | Free | Steam Charts | |
 | 12,724 | 11/15/2017 | 76 | Free | Steam Charts | |
 | 11,195 | 9/30/2021 | 48 | Free | Steam Charts | |
 | 7,630 | 12/29/2017 | 90 | Free | Steam Charts | |
 | 7,141 | 12/8/2023 | 77 | Free | Steam Charts | |
 | 5,616 | 10/17/2017 | 81 | Free | Steam Charts | |
 | 4,915 | 8/9/2024 | 93 | Free | Steam Charts | |
 | 4,478 | 11/9/2016 | 78 | Free | Steam Charts | |
 | 4,320 | 3/25/2024 | 84 | Free | Steam Charts |
Soures & References
Steambase has best-in-class data powered directly by Steam, our data partners, and in-house experts. Player counts and rankings are enriched, analyzed, and updated in real-time to ensure we surface the most up-to-date insights. Learn more about the Steambase approach to data collection and our review methodology.
- Valve Corporation. (2025, August 7). Steam Store. Steam Store.
- Valve Corporation. (2025, August 7). Counter-Strike 2 on Steam. Steam Store.
- Valve Corporation. (2025, August 6). Dota 2 on Steam. Steam Store.
- Valve Corporation. (2025, August 6). PUBG: BATTLEGROUNDS on Steam. Steam Store.
- Valve Corporation. (2025, August 7). Delta Force on Steam. Steam Store.
- Valve Corporation. (2025, August 7). Marvel Rivals on Steam. Steam Store.
- Valve Corporation. (2025, August 7). Warframe on Steam. Steam Store.
- Valve Corporation. (2025, August 7). Tom Clancy's Rainbow Six® Siege X on Steam. Steam Store.
- Valve Corporation. (2025, August 7). tModLoader on Steam. Steam Store.
- Valve Corporation. (2025, August 6). Team Fortress 2 on Steam. Steam Store.
- Valve Corporation. (2025, August 7). Once Human on Steam. Steam Store.