Minecraft trial chambers: the underground challenges of 1.21
Trial chambers are large underground structures added in the Minecraft 1.21 Tricky Trials update. They generate deep underground and work as procedurally generated combat arenas, where you face waves of mobs released by trial spawners. Every challenge you beat earns you a reward from a vault, including unique items like the mace and the wind charge. If you're looking for the best endgame content in 1.21, trial chambers are where you want to be.
How to find trial chambers
Trial chambers generate underground, most often between Y=-40 and Y=-20. Look for them in the stone layers deep below the Overworld. Unlike bastions or End cities, trial chambers aren't tied to a specific biome: they generate under any terrain.
The fastest way to find one is the command /locate structure minecraft:trial_chambers. If you're playing survival without cheats, dig down in new chunks and look for the telltale tuff and copper blocks. These are the main building materials of trial chambers and set them apart from natural stone.
The Trial Explorer Map is a special item you buy from a Journeyman-level cartographer villager. It leads you to the nearest trial chambers, the same way the Ocean Explorer Map leads you to an ocean monument. It's the best method in pure survival, although you first have to unlock that trade with the cartographer.
Room layout
Trial chambers are procedurally generated, so no two look the same. The rooms connect in a random arrangement, like a dungeon in a roguelike game. You'll find corridors, arena halls, puzzle rooms and reward chambers.
Room types
- Corridors - narrow passages connecting the bigger rooms. Some contain traps with dispensers that shoot arrows or TNT. Watch out for pressure plates on the floor.
- Arenas (encounter rooms) - big open halls with trial spawners in the middle. This is where the main fighting happens. Arenas come in different shapes and sizes, from small 7x7 rooms to multi-level halls with platforms.
- Reward rooms - rooms with vaults, which need a trial key to open. You get the key for defeating the mobs from trial spawners.
- Decorative halls - rooms with fountains, pillars and copper details. They often hold chests with smaller loot.
- Intersection rooms - hubs connecting several corridors. It's easy to get lost, so mark your way with torches.
Building materials
Trial chambers are built mainly from tuff bricks, polished tuff, copper in various stages of oxidation and trial spawner blocks. Over time the copper parts turn green (oxidize), which gives older sections of the structure their distinctive look. Tuff bricks are worth collecting: they're an attractive building material that doesn't generate anywhere else.
How trial spawners work
The trial spawner is a new type of spawner introduced in 1.21. Unlike classic monster spawners, a trial spawner adjusts the number of mobs to the number of players nearby and deactivates once you beat all its waves. That keeps the challenge scalable and fair for solo players and for groups on multiplayer servers alike.
How it works
- Activation: A trial spawner activates when a player comes within range (about 14 blocks). The block starts giving off particles and light.
- Spawning mobs: The spawner releases waves of mobs. For one player that's usually 2-3 mobs per wave, for four players it can be 6-8. The mob type depends on the spawner.
- Defeat: Once all the mobs are dead, the spawner deactivates and goes on cooldown. You can't use it again for 30 minutes.
- Reward: After deactivating, the spawner ejects a trial key, which you need to open a vault.
A classic spawner runs nonstop and you can build an XP farm around it. A trial spawner is a one-time challenge with a 30-minute cooldown. You can't farm it, but it gives unique rewards you won't get any other way.
Mobs in trial chambers
Trial chambers are the only place in the game where you'll meet the Breeze, a new mob added in 1.21. Besides the Breeze, trial spawners also produce standard hostile mobs, but under controlled conditions.
Breeze
The Breeze is a hovering mob that shoots wind charges. Its projectiles don't deal much direct damage, but they knock you back with tremendous force. In trial chambers, with plenty of platforms over drops, the knockback is often worse than the damage itself. The Breeze is fast and jumps around the arena, so it's hard to hit in melee. When it dies, the Breeze can drop breeze rods, which you craft into wind charges.
Other mobs
- Zombie and Husk - standard melee mobs. In trial chambers several of them often spawn at once.
- Skeleton and Stray - archers, dangerous in open arenas. Strays inflict Slowness.
- Spider and Cave Spider - fast, and they climb walls. Cave spiders poison you.
- Slime and Silverfish - smaller threats, but in large groups they get annoying.
- Baby Zombie - tiny, fast and surprisingly deadly. Thanks to its small hitbox, it's one of the most dangerous enemies in trial chambers.
Each trial spawner spawns one specific type of mob, so you can prepare for that threat before you activate it. Look at the miniature mob inside the trial spawner block.
Ominous trials: the harder mode
If you enter trial chambers with the Bad Omen effect, it changes into Trial Omen. This turns on ominous trial mode, which changes the rules.
What changes
- Trial spawners become ominous trial spawners - they spawn more mobs and tougher variants (for example mobs with armor and enchanted weapons).
- Ominous vaults - instead of regular vaults you get their ominous versions with better loot, including ominous bottles and unique enchantments. Read more about vaults in our separate guide.
- Extra traps - extra hazards appear in the arenas.
- Better rewards - the ominous trial key (instead of a regular trial key) opens an ominous vault with exclusive rewards.
Ominous trials are for players who want a bigger challenge. Get ready for a brutal fight: without a good combat strategy and solid gear, ominous mobs can kill you in seconds. Bring a potion of healing and a potion of strength.
Loot and rewards
Trial chambers are the only source of several unique items in the game. You get the rewards mostly from vaults, but also from chests scattered around the corridors.
Unique items from trial chambers
- Mace - a new weapon with a unique smash attack. The farther you fall, the more damage you deal. You craft it from a heavy core and a breeze rod.
- Heavy Core - the ingredient for crafting the mace, available only from ominous vaults.
- Trial Key / Ominous Trial Key - the keys that open vaults. You get them for defeating the mobs from trial spawners.
- Wind Charge - a throwable item that releases a gust of wind. You can use it to jump, knock back mobs and activate mechanisms.
- Breeze Rod - dropped by the Breeze, used to craft wind charges and the mace.
- New smithing templates - the Bolt and Flow armor trims for customizing your armor.
- New banner patterns - unique patterns found only in trial chambers.
Regular chest loot
Chests in the corridors and decorative halls contain copper, arrows (including tipped arrows), food, torches and building materials. They're not as impressive as vault rewards, but they help you restock during a long run.
Strategies for exploring trial chambers
Gear
- Weapons - a sword with Sharpness V for melee and a bow with Power V for skeletons. Also consider the mace if you already have one.
- Armor - full netherite or diamond with Protection IV. A shield is a must against the Breeze's wind charges.
- Food - golden carrots or golden apples for longer runs.
- Potions - Instant Health, Strength and Speed for the tougher fights.
- Blocks - cobblestone for blocking passages and building cover.
- Torches - trial chambers are dark. Lighting up the rooms stops extra mobs from spawning outside the trial spawners.
Room-by-room tactics
Don't rush blindly through trial chambers. Enter a room, activate the trial spawner, beat the waves of mobs, collect the trial key and move on. Close doors behind you or block corridors with cobblestone so mobs from one room don't follow you into the next. Leave torches in the rooms you've cleared as markers.
Arenas with several trial spawners are the hardest. If you see two or three spawners in one room, activate them one at a time: walk up to one, defeat its mobs, then move on to the next. Activating them all at once can overwhelm you, especially if there's a Breeze in the mix.
Frequently asked questions
Can trial chambers be reset?
No, but trial spawners have a 30-minute cooldown, after which you can activate them again. A vault, however, can be opened only once per player: each player opens it with their own key and gets their own reward.
What difficulty should I play on?
Trial chambers are balanced for Normal. On Hard, mobs deal more damage and are more likely to have extra effects. On Easy it's more of a walk in the park, though the Breeze can still catch you off guard.
Do trial chambers generate in Bedrock Edition?
Yes, since version 1.21 trial chambers are available in both Java and Bedrock Edition. The mechanics are identical on both platforms.
