Minecraft: How to blow up blocks underwater using TNT

Minecraft might seem like a simple game, but underneath the simple, blocky world, there are a lot of complicated gameplay mechanics that can get confusing at times. Out of all, perhaps the one that is most needed is making TNT explode and break blocks underwater. Sure, you can make TNT explode underwater and it will even cause damage to both the player and the mobs around it. But unfortunately, it will not break anything else in its vicinity, rendering the action useless.

So how can you make TNT break blocks underwater and make it useful? In this article, we will explain the process of making TNT work underwater for both the Java and Bedrock Editions of Minecraft.

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How to blow up TNT underwater in Minecraft Java

Making TNT explode underwater in Java Edition (Image via Reddit/Keanusw/Mojang Studios)

For the Minecraft Java Edition, making TNT explode underwater is very easy. When the TNT block is surrounded by water, the damage done by the blast is negated by the water. This is very similar to how water prevents any fall damage, no matter where you fall. So the trick is to make the game think that the TNT is not surrounded by water.

This can be done by placing a block that is affected by gravity, such as a sand block or gravel block. To make the TNT explode, place the TNT block and then place a block of sand or gravel above it.

Use a level of flint and steel to ignite the TNT. This will trigger it, causing the sand or gravel block to go inside the TNT block. This makes the game think the TNT is surrounded by solid blocks, making the explosion break nearby blocks.

Using these features of the TNT block can be extremely useful. Especially when you want to break large underwater areas for a treasure hunt, break down sunken ships, or even break open ocean monuments without going through the hassle of exploring them from the inside.

How to blow up TNT underwater in Minecraft Bedrock.

Making TNT explode underwater in Minecraft Bedrock (Image via Mojang Studios)

The method mentioned earlier will not work in Minecraft's Bedrock Edition. For some reason, when you place the sand or gravel block on top of the TNT block and ignite it, the TNT block floats above the sand block and explodes, doing damage but not breaking anything around it.

To get around this, the same principle can work, but we need to build a few extra things to ensure that the sand block goes inside the TNT when it explodes. To build this contraption, make sure you have a lever, a piston, and some wooden planks along with sand blocks.

The piston pushes the sand block while the wood stops TNT from moving aside. (Image via Mojang Studios)

Make a structure as shown in the image. We have placed sea lanterns to light up the structures. You do not have to do it. Make sure that the TNT is surrounded by solid blocks. We have used wood planks. You can use dirt or cobblestone. Place the piston next to the TNT and make sure that when it is activated, it pushes the sand block onto the TNT block.

Here’s the tricky part. The moment you ignite the TNT, quickly turn on the piston using the lever right at the moment it is about to explode. Time it perfectly and you will find the TNT exploding and breaking the blocks around it.