How to Find and Beat Trial Chambers in Minecraft

Guide Java Bedrock

Quick answer: Trial chambers generate underground in the deepslate layers, mostly between Y=-20 and Y=40. Buy a Trial Chamber map from a journeyman Cartographer villager, or explore caves below those depths. Inside, trial spawners scale the fight to your party size, vaults take trial keys, and ominous trials (drink an Ominous Bottle for Trial Omen) award ominous keys for the heavy core that crafts the mace.

What you need

Trial Explorer Map (cartographer) or cave exploration
Protection armor, shield, sword/axe and bow
Food, blocks, empty inventory slots
Ominous Bottle for ominous trials (optional, for heavy core)

Step by step

Get a map: journeyman-level Cartographers sell a Trial Explorer Map pointing to the nearest unexplored chambers. Exploring deepslate-layer caves (Y=-20 to 40) and watching for tuff-and-copper walls works too, and /locate structure minecraft:trial_chambers does it instantly with cheats.
Gear up like for a raid: Protection armor, shield, a strong melee weapon, a bow, food, and blocks. Bring empty inventory space for loot.
Fight the trial spawners: each one detects nearby players and spawns waves of a themed mob (melee, small melee or ranged: zombies, slimes, silverfish, spiders, skeletons, strays, breezes...). More players nearby means more mobs, so solo runs are very manageable.
Loot the decorated pots and chests in corridors for trial keys, then open the Vault blocks scattered through the chambers - each player can open each vault once.
For the real prize, go ominous: drink an Ominous Bottle (from raid captains or vaults) to gain Trial Omen inside the chambers. Spawners turn ominous, mobs spawn with gear and projectiles, and defeated ominous spawners can drop Ominous Trial Keys.
Ominous keys open Ominous Vaults, the high blocks with the red glow: these hold the best loot, including the Heavy Core - combine it with a Breeze Rod (from the Breeze, found only here) to craft the Mace.

Java vs Bedrock

Trial chambers are the same structure on Java and Bedrock, including trial spawner scaling, vaults, ominous trials and the cartographer map trade. Ominous vault loot tables and the mace recipe (heavy core + breeze rod) match on both. Bedrock combat is a little easier on the mace's smash attack timing, but the mechanics are shared.

Versions: Added in 1.21 (Tricky Trials). Current as of 26.3.

Frequently asked questions

How do you get the mace in Minecraft?

Craft it from a Heavy Core (ominous vault loot in trial chambers) plus a Breeze Rod dropped by the Breeze, a trial chambers mob. It is the only source of both items.

What is the difference between a vault and an ominous vault?

Regular vaults open with trial keys and give mid-tier loot. Ominous vaults (taller, red-glowing) only open with ominous trial keys from ominous trial spawners and hold the top loot: heavy cores, enchanted golden apples, flow and bolt armor trims, and the best enchanted books.

Do trial spawners ever stop spawning?

Each spawner has a per-player cooldown after you defeat it (about 30 minutes in real time), then it can be fought again. They cannot be mined or moved, so the chambers are a repeatable combat arena.