If you're at school, the chances are that most of the gaming sites you know are blocked. Firewall rules on school networks typically catch anything with "games" in the domain name or metadata. But IO games â the lightweight, browser-based multiplayer titles that defined a generation of online gaming â are different. Many of them are tiny in file size, load via HTTPS, and look innocuous enough to pass filters. And when they don't, there are network portals specifically built to work around those blocks legally.
This guide covers the ten best IO games you can realistically play at school in 2026, plus advice on which portals tend to work on managed Chromebooks without needing admin permissions.
Why IO Games Work at School
IO games tend to pass content filters for several reasons:
- Simple domains: Sites like
slither.ioorkrunker.iodon't look obviously "gaming" to a basic keyword filter. - No downloads: Because they run entirely in the browser with no executable files or plugins, they don't trigger download-based security policies.
- Lightweight: Most IO games load under 5MB and run on even low-powered Chromebook hardware.
- HTTPS: Properly secured sites are less likely to be blanket-blocked than HTTP sites.
When the direct site is blocked, Unblocked G+ hosts embedded versions of many popular IO titles that work through most standard school network restrictions.
The 10 Best Unblocked IO Games for School
1. Slither.io
Slither.io is the closest thing to a universally unblocked game. It's been around since 2016, runs on minimal data, and even works on older Chromebooks with slow WiFi. The gameplay loop â grow your snake, trap opponents' heads with your body to eliminate them â is as compelling in 2026 as it was a decade ago. A single session can last anywhere from thirty seconds to twenty minutes depending on how long you survive.
Controls are mouse-only (or touch on mobile), making it one of the most accessible IO games for shared keyboard situations. Slither.io remains one of the top unblocked game searches every year for a reason.
2. Krunker.io
Krunker.io is a browser-based first-person shooter that consistently ranks as the highest-quality IO game available. The graphics are intentionally blocky (similar to Roblox), which means the game runs smoothly on any hardware and passes most "violent content" filters on school networks. The gunplay is snappy, the maps are well-designed, and there are consistent updates adding new weapons and game modes.
Multiple game modes are available: Team Deathmatch, Free for All, Capture the Flag, and more. Custom lobbies let you create private games with just your friends. This is the IO game that's genuinely competitive â there are professional Krunker players and a ranked ladder if you want to improve seriously.
3. Agar.io
The original massive IO hit. You control a circular cell; eat smaller cells (including other players) to grow; avoid larger cells. Agar.io introduced the IO game format to the mainstream and its mechanics remain elegantly simple. The strategy layer is surprisingly deep â when to split, how to trap opponents, how to cooperate in team modes â and it all emerges naturally from the simple ruleset.
The official Agar.io domain is sometimes blocked, but hosted versions on Poki2's unblocked portals are accessible on most school networks.
4. Paper.io 2
Paper.io 2 puts you in a coloured square trying to expand your territory by drawing lines across open space. The catch: if any other player crosses your line while you're outside your territory, you're eliminated. The risk-reward dynamic of extending your territory while staying close enough to safety keeps every session tense. It's a perfect five-minute game â visually clean, easy to understand, and available at AZ Games.
5. Wormate.io
Wormate.io adds a twist to the Slither formula: instead of a plain arena, the ground is covered in candy and cakes that your worm eats to grow. Power-ups scattered around the map change the speed, size, or abilities of your worm temporarily. The visual design skews younger and is unlikely to trigger school content filters. The gameplay is more chaotic than Slither due to the speed power-ups, which suits shorter play sessions.
6. Surviv.io
Surviv.io is a top-down battle royale IO game â think PUBG mechanics in a browser window. A shrinking circle drives players together, loot spawns around the map, and the last player (or team) alive wins. Rounds typically take 5-15 minutes in squad mode and 3-8 minutes solo. The top-down perspective and cartoonish visuals pass most violence filters, and the game is hosted on multiple unblocked portals.
Surviv.io has a particularly active community and regular map/weapon updates, keeping it competitive with standalone battle royales for browser-based play.
7. Skribbl.io
Skribbl.io is the multiplayer drawing and guessing game. One player draws a chosen word; everyone else tries to guess it. It's IO in format (no download, browser-based, real-time multiplayer) but it's not a combat or elimination game â it's creative and communicative. For this reason it rarely triggers school content filters, and it's genuinely fun as a group activity during a free period.
Custom word lists let you create themed games specific to subjects you're currently studying, which genuinely makes it one of the few multiplayer browser games a teacher might actively endorse.
8. Diep.io
Diep.io puts you in control of a tank that shoots geometric shapes to earn points, which you invest in upgrades â bullet speed, bullet damage, movement speed, reload time, and more. As you level up, you choose from branching upgrade trees that define your playstyle. The complexity ramps gradually enough that new players can participate without understanding all the mechanics, while veterans exploit builds and strategies that go surprisingly deep.
9. Shell Shockers
Shell Shockers is a first-person shooter where every player is an egg armed with various egg-themed weapons. The visual absurdity makes it unlikely to trigger violence filters, while the gameplay is a legitimately well-made FPS with good hit detection, varied weapon classes (sniper, shotgun, assault rifle), and team modes. It's one of the most-played IO shooters on unblocked portals precisely because its visual style is hard to object to.
Available directly at AZ Games.
10. Gartic.io
Gartic.io is similar to Skribbl but with additional game modes: Icebreaker, Animation, Soundtrack, Knock-Off, and more. The variety keeps it interesting at a classroom level, and the custom room feature means you can play with exactly your friend group using a private link. Like Skribbl, the creative and communicative nature means it's rarely blocked and sometimes encouraged.
Best Unblocked Game Portals for School
Unblocked G+
Unblocked Games G+ is our dedicated school-safe portal with 474+ games. The domain is not on the common blocklist databases used by school network equipment, and all games load via HTTPS. It works on standard Chromebook configurations without requiring any extensions or VPNs. Most of the IO games listed above are available here.
Tips for Chromebook users
- Use Chrome (not a third-party browser) to ensure WebGL works for 3D IO games like Krunker.io.
- If a game fails to load, try clearing site data: Settings â Privacy â Clear browsing data â Cached images and files.
- Games that use WebRTC (peer-to-peer connections) may fail on very restrictive networks â Krunker.io and Surviv.io use dedicated servers and typically work better than pure P2P titles.
- Older Chromebooks (pre-2018) may struggle with 3D games. Stick to 2D IO titles like Slither.io, Paper.io 2, and Agar.io for best performance.
What to Do If Everything Is Blocked
If your school uses a strict content filter like Securly, Lightspeed, or GoGuardian, individual game sites may still be blocked even when accessed through a portal. In that case:
- Turn-based games and pure text games (like browser chess or browser Wordle variants) almost never get blocked.
- Skribbl.io and Gartic.io rarely trigger filters because they're drawing/creative tools.
- Browser puzzle games (2048, Sudoku, crosswords) are categorised as "educational" by most filters and pass through without issue.
The Unblocked G+ portal is specifically designed to pass most filter systems while keeping the full game experience intact. If you can't find a working game anywhere else, start there.
