Slime Height Spawn 69–150

Slime Height 69–150

Slime Height 69–150 is a lightweight Minecraft Java Edition datapack that allows slimes to spawn in swamp biomes at much higher Y-levels than vanilla normally allows.

The datapack is designed for slime farms built at higher elevations while keeping the rest of the slime mechanics as close to vanilla as possible.

Features
🟢 Allows slime spawn attempts from Y=69 to Y=150
🚫 Never spawns slimes above Y=150
🌿 Works specifically in swamp biomes
🟢 Supports small, medium, and large slimes
🚫 Prevents spawning on slabs
💡 Checks for suitable spawning space
🔧 Does not modify slime-chunk generation
📦 Server-side datapack — players do not need to install anything on their clients
⚡ Lightweight and suitable for multiplayer servers
How It Works

Minecraft datapacks cannot directly modify the hard-coded height limit used by the vanilla slime spawning algorithm. Instead, this datapack adds its own spawn attempts in valid swamp locations.

The target Y-level is randomly selected between:

Y=69 … Y=150

This means the datapack can be used for farms at different elevations without allowing spawns above Y=150.

Compatibility

Minecraft Java Edition 26.3

Designed for vanilla-style multiplayer servers and compatible with server software that supports standard Minecraft datapacks.

Installation
Download the datapack.
Place the ZIP file in your world’s datapacks folder.
Start or restart the server.
Use:
/datapack list

to verify that the datapack is enabled.

Notes

This datapack adds extra slime spawn attempts rather than changing Minecraft’s internal Java spawning code. Because of this, its spawning behavior is not identical to the native vanilla spawning algorithm in every detail.

It is intended primarily for high-altitude swamp slime farms where the normal vanilla height restriction prevents slime spawning.

No client-side installation is required.