Updated 25 October 2026. Facts on this page come from minecraft.wiki, community sites named in the text and the live Artemis PvP server; sources are listed at the bottom.
How to Make TNT Break Blocks Underwater
In Java Edition, put a block of sand, gravel or concrete powder on top of TNT before you light it. When the TNT turns into an entity, the sand falls into its space, so the TNT explodes inside the sand instead of the water and breaks blocks around it. This works for clearing ocean monuments.
What are the steps?
- Take 1 TNT, 1 sand, gravel or concrete powder, and flint and steel.
- Place the TNT in or near the water, with the sand or gravel on top.
- Light the TNT and move well away.
That is minecraft.wiki's underwater TNT tutorial, which suggests it for destroying ocean monuments.
Why does it work?
The tutorial explains that the TNT does not really explode in water: when lit, the TNT block becomes a primed TNT entity, the falling block drops into the same space, and the explosion happens inside the sand or gravel. Normally water's high blast resistance shields the blocks around an underwater explosion. The TNT page lists the same rule, and notes TNT lit on top of a block shorter than full (like soul sand or honey) can also break blocks.
Is there another method?
Yes, a more expensive one: surround the TNT with blocks of low blast resistance, or put it in a one-block hole, so only its top touches water, then place a redstone block on top to light it. The tutorial notes a redstone block is used because it works as a signal source underwater.
Does this work on Bedrock?
No. minecraft.wiki says Bedrock TNT cannot break blocks underwater by any of the Java methods: falling blocks only partly push the primed TNT aside. Bedrock with Education Edition features has Underwater TNT instead. See Bedrock TNT.
How does this relate to raiding water walls?
It is the same principle as a hybrid cannon: get solid sand where the water was so TNT can break things. Raiders do it at range with cannons. See hybrid cannons, TNT and water and falling blocks.
Frequently asked questions
Can TNT break blocks underwater?
Not normally, but in Java you can put sand or gravel on top before lighting it so it explodes inside that block.
How do you clear an ocean monument with TNT?
Use the sand-on-top trick from minecraft.wiki's underwater TNT tutorial.
Sources
Every fact on this page was checked against these pages; the wording is ours.