How to Build a Guardian Farm: 3 Ways, Boat to Full Drain

A guardian farm uses the fact that guardians keep spawning in the water inside an ocean monument’s structure area, forever, at any light level. Build something that moves those guardians to one spot and kills them, and you get one of the biggest XP sources in the game, plus prismarine shards, prismarine crystals and fish.

There’s no single design. How much you build depends on how much time you want to put in, so here are three levels of effort.

Before you build anything

Every version starts the same way: clear the ocean monument.

• Kill all three elder guardians. They inflict Mining Fatigue III on anyone nearby, which makes breaking blocks painfully slow. One sits in the top room and the other two are in the wings. They don’t respawn, and each drops a wet sponge, which you’ll want later.
• Bring water breathing. A Potion of Water Breathing, a turtle shell helmet or the Respiration enchantment. Depth Strider on boots and night vision help a lot.
• Bring milk to clear Mining Fatigue if an elder guardian catches you.

Level 1: hunting from a boat

The no-build option. Sit in a boat or stand on a small platform just above the monument and kill guardians with a sword as they come up to attack you. It’s slow and you’ll take some laser damage, but it gets you a few stacks of prismarine shards for sea lanterns or a conduit frame without any construction.

Level 2: a funnel without draining

Guardians spawn inside the monument’s area wherever there’s water, from the ocean floor up to sea level. You can direct them without draining anything:

• Build a platform of glass or other solid blocks just under the surface, above the monument, so guardians spawn below it but not above it.
• Use flowing water or magma-block bubble columns to drag guardians to a single point.
• Pull them out through a tube and drop them into a small chamber where you can hit them.

This is a weekend project and the rates are much better than hunting from a boat.

Level 3: the drained monument

The famous high-rate farms empty the whole monument area of water and replace it with a stack of controlled spawning platforms. It’s a large project:

1. Wall off the monument’s footprint, 58×58 blocks, with walls up to sea level.
2. Drain it section by section using sponges (dry the elder guardians’ wet sponges in a furnace and reuse them) or by filling the water with sand and digging it out.
3. Demolish the monument itself if you want. The prismarine isn’t what makes guardians spawn.
4. Build layers of water spawning platforms with flowing water that carries guardians into a central drop chute.
5. Kill them at the bottom yourself for XP, or with a trap for drops only.

Expect this to take several evenings. If you’re on a server, check the rules on structure clearing first.

What the drops are for

Prismarine shards build prismarine blocks, bricks and dark prismarine. Shards plus crystals make sea lanterns, the brightest underwater light. The XP is the main prize: a working farm fills an enchanting bar quickly and pays for Mending repairs on everything you own.

For something cheaper in the same ocean setting, a drowned farm can be built in a river with far fewer blocks.