Ocean Monument structure in Minecraft

How to find an Ocean Monument

Monuments only generate in the four deep ocean biomes, such as the Deep Ocean, and the game also checks that the water around them is ocean or river. That keeps them in open sea, well away from coasts. There is at most one per 32 × 32 chunk region, with at least 5 chunks between two of them.

The building is 58 × 58 blocks and rises from Y 39 to just under the surface, so its roof is often visible from a boat as a pale square of prismarine in the dark water. If you would rather not search, a Cartographer villager sells an Ocean Explorer Map that points to the nearest monument, and the /locate command above does the same in creative or with cheats on.

Guardians, Elder Guardians and Mining Fatigue

Guardians spawn inside the whole volume of the monument in groups of two to four, and they keep spawning after you have cleared a room. They lock on with a laser that charges for a moment before it hits, so breaking line of sight behind a pillar cancels the attack. When their spikes are out, hitting them in melee hurts you back.

The real threat is the three Elder Guardians: one in each wing and one in the top room. They do not respawn. Every so often they curse every player nearby with Mining Fatigue III, announced by a ghostly face on your screen. At that level, digging through prismarine takes ages, so plan to kill all three before you mine anything. A Milk Bucket clears the effect, but it comes back as long as one of them is alive.

What to bring before you dive

• Air. Several Potions of Water Breathing are the single most useful item. A helmet with Respiration buys extra time, and a door placed underwater leaves a pocket of air you can breathe in.
• Light. The halls are dim; a Potion of Night Vision makes navigation much easier.
• Speed. Boots with Depth Strider let you move almost normally, and Aqua Affinity removes the underwater mining penalty.
• Milk and food. Two or three buckets of milk for the Mining Fatigue, plus food that heals fast.

If you already own a Conduit, set it up with a small prismarine frame near the entrance. It gives Conduit Power: water breathing, better sight and faster mining in one effect.

What's inside: gold, sponges and the core

The monument holds no chests. Its treasure is built into the walls. At the bottom of the main hall, the core room hides eight Blocks of Gold inside a shell of Dark Prismarine. Look for a closed cube in the middle of a room lit by Sea Lanterns and break it open.

Some dead-end rooms on the upper levels are packed with Wet Sponges. Dry them in a furnace to get reusable Sponges, the best tool for draining water. Each Elder Guardian killed by a player also drops one Wet Sponge, and has a one in five chance to drop the Tide armor trim smithing template.

How to raid an Ocean Monument efficiently

• Go in through the front arch. It leads to the central hall; the two wings sit on either side of the entrance.
• Kill the Elder Guardians first. Clear both wings, then climb to the top room for the third one. The Mining Fatigue disappears for good once they are gone.
• Mark your route. Rooms look alike and the layout changes from one monument to the next. A trail of torches on the floor or blocks of another colour stops you from going round in circles.
• Collect the sponges, then the gold. With sponges in hand, you can dry out the core room before breaking the gold.

What to do with a cleared monument

Because Guardians keep spawning inside the structure, a drained monument is the classic spot for a guardian farm: a steady supply of Prismarine Shards, Prismarine Crystals and fish. The walls themselves are a huge stock of prismarine blocks, and Sea Lanterns drop crystals if you break them without Silk Touch. Many players also turn the shell into an underwater base, with a Conduit at the centre to keep the area safe.

✓ Checked in Java Edition 26.3 · updated 1 November 2026