All IO Games List – Updated 2025 List

If you’ve ever found yourself hooked on a quick, competitive browser game, chances are you’ve played an IO game. These online multiplayer games, known for their “.io” domain extension, have taken the gaming world by storm with their simplicity, accessibility, and addictive gameplay. From battling it out in Agar.io to surviving zombie hordes in Zombs.io, IO games have built massive communities of players who love the thrill of real-time competition. In 2025, IO games remain as popular as ever, evolving with new titles, features, and communities while staying true to their minimalist roots. Let’s dive into what makes IO games so special, how to play them, and a curated list of the best ones to try this year—around 1200-1500 words of straightforward, engaging insight. Jump to the games list 👉

What Are IO Games?

IO games are online multiplayer games hosted on websites with a “.io” domain, a suffix originally tied to the British Indian Ocean Territory but now widely used for gaming sites due to its catchy, tech-friendly vibe. These games are typically browser-based, meaning you can play them directly in your web browser without downloading any software. They’re designed to handle large numbers of players at once—sometimes hundreds in a single match—making them perfect for quick, competitive fun.

What sets IO games apart is their simplicity. Most have minimalist graphics, often featuring basic shapes like circles or cubes, which keeps them lightweight and easy to run on a variety of devices, from high-end gaming PCs to budget laptops or even mobile phones. The gameplay usually revolves around competition or survival: you might be collecting resources, building a base, or fighting to be the last player standing. Think of Agar.io, where you control a cell that grows by eating smaller cells, or Slither.io, where you navigate a snake to gobble up pellets while avoiding collisions with others.

In 2025, IO games have evolved but retained their core appeal. They’re still free to play, accessible with just a stable internet connection, and perfect for jumping into a match during a lunch break or late-night gaming session. With millions of players worldwide—Agar.io alone has seen over 100 million players since its launch in 2015—IO games continue to thrive, spawning new titles and communities while keeping the classics alive.

Why Are IO Games So Popular?

The popularity of IO games in 2025 comes down to a few key factors. First, they’re incredibly easy to access. You don’t need to download an app or install software—just open your browser, visit the game’s website, and you’re in. This accessibility makes them a go-to for casual gamers who want quick fun without commitment. Whether you’re on a Chromebook at school or a smartphone during a commute, IO games load fast and run smoothly thanks to their lightweight design.

Second, the gameplay is simple yet addictive. Most IO games have straightforward mechanics—control a character, collect resources, or fight opponents—but the challenge of competing against real players keeps you coming back. In Surviv.io, for example, you’re dropped into a battle royale where every match feels intense as you scavenge for weapons and fight to be the last one standing. The competitive nature, combined with short match times (often 5-10 minutes), makes them perfect for quick bursts of entertainment.

Third, IO games foster community. Many have built massive online followings, with players sharing strategies on platforms like Reddit and Discord. In 2025, Krunker.io boasts over 50,000 daily active users, with Discord servers dedicated to clans, tournaments, and custom maps. The multiplayer aspect—where you’re often pitted against dozens or hundreds of players—creates a social vibe, especially when you can team up with friends or chat with opponents in-game.

Finally, they’re free to play, though many generate revenue through ads or optional in-game purchases like skins or upgrades. You can enjoy Paper.io without spending a dime, but if you want a shiny new skin for your cube, you might drop $2.99 on a cosmetic pack. This freemium model keeps IO games accessible while supporting developers to keep the servers running.

Can I Play IO Games Without Downloading?

Yes, one of the best things about IO games is that they’re browser-based, so you don’t need to download anything. In 2025, most IO games—like Agar.io, Slither.io, and Krunker.io—are still playable directly on their websites. Just open your browser (Chrome, Firefox, or Safari work great), visit the game’s site, and start playing. For example, to play Hole.io, you’d go to hole.io, click “Play,” and you’re instantly dropped into a match where you control a black hole gobbling up everything in sight.

This no-download approach makes IO games perfect for playing on shared or low-spec devices, like a school laptop or an older tablet. All you need is a stable internet connection—most games require a ping under 100ms for smooth gameplay—and a device with a modern browser. Some IO games, like Skribbl.io, even have mobile-optimized versions, so you can play on your phone without an app, though a few, such as Krunker.io, offer optional downloadable clients for better performance on PC.

Can I Play IO Games with Friends?

Absolutely—most IO games are built for multiplayer action, and playing with friends is a big part of the fun. In 2025, many IO games make it easy to connect with buddies. Here’s how you can do it:

• Share the Link: Most games let you join a match via a simple URL. For example, in Slither.io, you can copy the game link from your browser and send it to a friend through Discord or WhatsApp. They’ll join the same server, and you can slither around together, trying to outgrow other snakes.
• Private Rooms: Games like Skribbl.io (a drawing and guessing game) and Gartic.io let you create private rooms. In Skribbl.io, click “Create Private Room,” set a language and number of rounds, and share the room code with friends. You can then draw and guess together without random players jumping in.
• In-Game Friends Lists: Some IO games, like Krunker.io, have friend systems where you can add players and join their matches directly. In Krunker.io, you can search for a friend’s username, join their server, and team up for a first-person shooter match.

Playing with friends adds a social layer to IO games, whether you’re battling it out in Surviv.io or building a farm together in MooMoo.io. Many players in 2025 use Discord to coordinate, with servers for games like ZombsRoyale.io hosting voice chats where friends can strategize during matches.

How to Unblock an IO Game in 2025

Sometimes, IO games might be blocked on your school, work, or public network due to content filters. If you’re trying to play Agar.io during a break but the site won’t load, here are a few ways to unblock it in 2025:

• Use a VPN: A Virtual Private Network (VPN) masks your IP address, letting you bypass network restrictions. Free options like ProtonVPN or paid services like NordVPN (starting at $3.99/month) can help. For example, connect to a U.S. server, then visit slither.io—it should load without issues. VPNs also encrypt your connection, adding a layer of privacy.
• Try a Proxy Server: A proxy acts as an intermediary between your device and the game’s server, hiding your location. Sites like Hide.me or Kproxy offer free proxies—enter the game’s URL (e.g., surviv.io), and you’re good to go. Proxies are often slower than VPNs but can work in a pinch.
• Use a Web Proxy: Similar to a proxy server, a web proxy lets you access blocked sites through a browser-based interface. Services like Proxysite.com are free—type in the game’s URL, and it’ll load the site anonymously. This method is handy for quick access but may not support all game features.
• Switch Browsers: Some networks block sites on specific browsers due to cached filters. If Hole.io won’t load on Chrome, try Firefox or Safari. In 2025, browsers like Microsoft Edge also have built-in “Kids Mode” that might block games, so using a different browser can help.

A word of caution: while these methods can unblock IO games, they might not always work if your network has strict firewalls, like those in schools using advanced filtering software. Also, using VPNs or proxies can slow your connection—expect a ping increase of 20-50ms—and may violate network policies, so proceed with care. Always stick to trusted services to protect your privacy, and avoid sketchy sites that could expose your device to malware.

Are IO Games Free to Play?

Yes, most IO games in 2025 are free to play, which is a big reason for their popularity. Developers typically make money through in-game ads, microtransactions, or sponsorships, allowing them to offer the core game at no cost. For example, Agar.io displays banner ads between matches, while Krunker.io offers optional purchases like weapon skins for $1.99-$4.99. These purchases are cosmetic and don’t affect gameplay, so you can enjoy the full experience without spending a dime.

Some games, like ZombsRoyale.io, have battle passes—think $5 for a season pass that unlocks exclusive skins or emotes—but they’re optional. The free-to-play model keeps IO games accessible, especially for younger players or those who don’t want to commit to paid games. With a stable internet connection (at least 10 Mbps for smooth play), you can jump into a match of Diep.io or Paper.io without ever opening your wallet.

The Best IO Games to Play in 2025: A Curated List

Here’s an updated list of the best IO games to try in 2025, including classics and new titles that have gained traction. Each game is free, browser-based, and perfect for quick, competitive fun.

• Agar.io: Control a cell and eat smaller cells to grow larger while avoiding being eaten. It’s the game that started the IO craze, with over 100 million players since 2015. Play at agar.io.
• Slither.io: Navigate a snake to eat glowing pellets, growing longer while avoiding collisions with other snakes. It’s still a fan favorite with 500,000 daily players. Play at slither.io.
• Surviv.io: A top-down battle royale where you scavenge weapons and fight to be the last one standing. Recent updates in 2025 added new maps and skins. Play at surviv.io.
• Hole.io: Control a black hole, gobbling up cars, buildings, and even other holes to grow bigger in a 2-minute match. It’s chaotic fun with 300,000 monthly players. Play at hole.io.
• Krunker.io: A fast-paced first-person shooter with Minecraft-like graphics. In 2025, it boasts 50,000 daily players and new custom maps. Play at krunker.io.
• Bonk.io: A physics-based multiplayer game where you bounce opponents off the map. It’s simple but addictive, with new levels added this year. Play at bonk.io.
• MooMoo.io: Build a farm, gather resources, and defend against other players in this survival game. A 2025 update added new weapons like the katana. Play at moomoo.io.
• Diep.io: Control a tank, shoot enemies, and upgrade your stats in this tank battle game. It’s a classic with a steady 200,000 monthly players. Play at diep.io.
• ZombsRoyale.io: A zombie-themed battle royale with 100-player matches. It’s gained traction with Discord communities hosting tournaments. Play at zombsroyale.io.
• Paper.io: Claim territory by drawing lines with your cube, but don’t get caught by other players. A 2025 update added team modes. Play at paper.io.
• Starve.io: Survive in a harsh wilderness by crafting tools and building a base. Recent updates include new biomes like a desert map. Play at starve.io.
• FlyOrDie.io: Evolve your creature by eating others in this food chain survival game. It’s a quirky favorite with 150,000 monthly players. Play at flyordie.io.
• Deeeep.io: An underwater adventure where you evolve from a fish to a shark, exploring biomes like the Arctic. Play at deeeep.io.
• Skribbl.io: A drawing and guessing game where you sketch prompts for others to guess. It’s perfect for friends, with 400,000 monthly players. Play at skribbl.io.
• Lordz.io: Build an army and conquer opponents in this medieval strategy game. A 2025 update added new units like archers. Play at lordz.io.
• Shell Shockers: A first-person shooter with egg characters—think Call of Duty but with eggs. It’s hilarious and competitive. Play at shellshockers.com.
• Hordes.io: A multiplayer battle game with RPG elements, where you fight enemies and level up. Play at hordes.io.
• Brutal.io: Control a ball with a flail to smash opponents in this chaotic arena game. Play at brutal.io.
• Superhex.io: Surround territory with a line to claim it, but don’t let others cut you off. Play at superhex.io.
• Mope.io: Evolve your animal by eating others in this survival game. A 2025 update added new predators like a polar bear. Play at mope.io.

New and Trending IO Games in 2025

• HexSweep.io: A puzzle game where you flag mines on a hexagonal grid, similar to Minesweeper but multiplayer. Play at hexsweep.io.
• BulletLeague.io: A fast-paced FPS with pixelated graphics, featuring new maps in 2025. Play at bulletleague.io.
• Devast.io: Survive in a post-apocalyptic world by crafting and building. It’s gained 100,000 new players this year. Play at devast.io.
• CastleWars.io: Build and defend a castle while attacking others in this medieval strategy game. Play at castlewars.io.

Why IO Games Are Still Thriving in 2025

In 2025, IO games remain a staple of casual gaming, with millions of players logging in daily for quick, competitive matches. Their simplicity—minimalist graphics, easy controls, and short playtimes—makes them accessible to everyone, from kids on Chromebooks to adults on lunch breaks. The multiplayer aspect keeps things exciting, as you’re always up against real people, not bots, which adds a layer of unpredictability and thrill.

The community around IO games has grown stronger, with platforms like Discord hosting servers for games like Krunker.io and ZombsRoyale.io, where players organize tournaments and share custom skins. Developers continue to update classics—Agar.io got a new “team mode” in 2025—while new titles like HexSweep.io bring fresh ideas to the genre. Whether you’re battling in Surviv.io, drawing in Skribbl.io, or building in MooMoo.io, there’s an IO game for every mood. So, grab a friend, pick a game from our list, and dive into the fun—no download needed!