Borderlock is a game mode in which the world border is set to 1 block, and the radius increases by 1 block each ingame day.
You can either put the datapack inside the world before you generate it, or you put it in afterwards, but then you have to /reload.
Both available versions will work in either version, I just made it so that when you load the datapack it will not be marked as outdated.
If you don't want to start with just 1 Block and basically wait the first 20 minutes before starting to do something, you can use this command: "/worldborder add 2". I recommend increasing it by even numbers because this way it will always end on the edge of a block.
- Edition: Minecraft Java
- File type: .jar
- Minecraft version listed: 1.21.4
- 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 — see the MC Java Mods guides for the full walkthrough.
- Downloads as Borderlock 1.21.4.zip
- Download size: 3 KB
- Download link checked 7 Sept 2026 — working
These come from our own check of the pack file, not from the source page.