
Unstable Underworld
Java mod listed for Minecraft 1.21–26.x. Downloads from the MC Java Mods app on Android.
This datapack is inspired by the Unstable Underworld and adds the Unstable Underworld below the nether. There is no nether bedrock.
I don't know my version or loader





This Datapack adds the unstable inspired Underworld Dimension to minecraft.
Below the nether, if you dig, you will not find bedrock. Instead, you will find void, And that void, that void will lead to The Underworld!
Now, will you make your leap into the unknown or will you stay away because you are scared? (Credits to the Unstable SMP)
Features --
Entry
You must dig down, you won't find bedrock and there will be void, when you fall down, you will not take fall damage or die to the void, instead, you will go to The Underworld.
Exit
You must make a nether portal, that nether portal must be a perfect nether portalNether Portal Image
You must make a nether portal with 5 obsidain height and 4 on the bottom oresle it will not work.
Biomes
There is 5 new biomes in the underworld. All were seen in videos by the Unstable Creators.
- Edition: Minecraft Java
- File type: .jar
- Minecraft versions listed: 1.21.5, 1.21.6, 1.21.7
- How to install: Install the matching mod loader (Forge, Fabric or NeoForge) for your Minecraft version. → Download the .jar. → Put it in the .minecraft/mods folder and launch that loader profile.
- Where to get it: Opens on Modrinth — not every file is mirrored on our own servers.
Install steps are the general flow for this file type — How to install Minecraft Java mods & modpacks walks through it step by step.
- Ships as unstableunderworld-1.jar — drop this file into the mods folder
- Download size: 148 KB
- Download link checked 28 Sept 2026 — working
These come from our own check of the pack file, not from the source page.