ModsFinder

Underground Worlds

by HexagonNico

With Underground Worlds, players can explore underground biomes, dungeons and a few surface structures, with each piece switched through a config file.

FabricForgeNeoForgeClient and serverCreative Commons Attribution Non Commercial No Derivatives 4.01.19.4 – 26.2

What it does

The mod began as an underground jungle biome with a jungle temple. Later the author folded more biomes into the same project, so that each can be switched on or off in the config file instead of living in a separate mod. The config can also turn off individual features for each biome.

Each biome and structure comes with its own feature set, and some bring exclusive mobs, tools and other items. A full list of features is kept on the project wiki. Underground Worlds needs Fabric API on Fabric and Forge Config API Port on Forge and NeoForge. Optional companions include Biolith, Curios API, Friends&Foes, Lithostitched, TerraBlender and Variants&Ventures. The mod runs on client and server, and files exist for 1.19.4 – 26.2 across Fabric, Forge and NeoForge, released under the Creative Commons Attribution Non Commercial No Derivatives 4.0 license, so it is not open source.

Key features

  1. Underground biomes

    Several underground biomes generate below the surface, each with its own terrain and set of features.

  2. Underground dungeons

    Dungeons placed underground hold their own mobs and loot, and a few structures also appear above ground.

  3. Biome and structure toggles

    Every biome has a switch in the config, and individual features can be turned off per biome.

  4. Exclusive mobs and items

    Biomes and structures can add their own mobs, tools and special items that are not found elsewhere.

Compatibility

Latest build for each game version and loader.

26.x4 of 4 versions with builds
26.23.2.1-26.23.2.1-26.23.2.1-26.1
26.1.23.2.1-26.13.2.1-26.13.2.1-26.1
26.1.13.2.1-26.13.2.1-26.13.2.1-26.1
26.13.2.1-26.13.2.1-26.13.2.1-26.1
1.21.x4 of 4 versions with builds
1.21.103.0.2-1.21.103.0.2-1.21.103.0.2-1.21.10
1.21.83.0.2-1.21.83.0.2-1.21.83.0.2-1.21.8
1.21.43.0.2-1.21.43.0.2-1.21.43.0.2-1.21.4
1.21.13.0.2-1.21.13.0.2-1.21.13.0.2-1.21.1
1.20.x4 of 4 versions with builds
1.20.420.3.120.3.1Not available
1.20.320.3.220.3.2Not available
1.20.220.2.120.2.1Not available
1.20.13.0.1-1.20.13.0.1-1.20.1Not available
1.19.x1 of 1 version with builds
ReleaseBetaAlphaNot available

Only full game releases are shown. This mod publishes no snapshot builds.

Requirements

Dependencies declared by the latest file for each loader.

Required 2

Fabric APILightweight and modular API providing common hooks and intercompatibility measures utilized by mods using the Fabric toolchain.
Required
Forge Config API PortNeoForge's & Forge's config systems provided to other modding ecosystems. Designed for a multiloader architecture.
Required

Optional 5

Friends&Foes (Fabric/Quilt)Adds outvoted and forgotten mobs from the mob vote, expanding on their original concepts and adding new vanilla-like features. The mod includes: Copper Golem, Crab, Glare, Moobloom, Iceologer, Rascal, Tuff Golem, Wildfire, Illusioner, Zombie Horse
Optional
Variants&VenturesAdds multiple new mob variants seamlessly integrated into your Minecraft world.
Optional
BiolithA biome placement mod focusing on configurability and consistent distribution of modded biomes
Optional
TerraBlenderA library mod for adding biomes in a simple and compatible manner!
Optional
LithostitchedLibrary mod with new configurability and compatibility enhancements for worldgen
Optional

Use cases

Adding caves to a survival world

Players who want more to find underground can generate the biomes and dungeons in an existing world while keeping the rest of the terrain.

Tailoring a modpack

Pack makers can keep only the biomes they want by disabling the rest in the config file.

Who it’s for: Players and server owners who want a configurable set of underground biomes and dungeons, and pack makers who need to choose which of them ship.

How it compares

Full comparison

Kubek's dungeons is a server-side dungeon mod for Fabric, Forge, NeoForge and Quilt, covering 1.21.4 – 26.1.2, and it is under All rights reserved, not open source. Epic Structures: Igloo is also server required, with client optional, and covers 1.19 – 26.3 on the same four loaders, under All rights reserved. Underground Worlds instead runs on client and server and focuses on underground biomes with a config for each one.

ModLoadersGame versionsEnvironmentUpdated
Underground WorldsFabric, Forge and NeoForge1.19.4 – 26.2Client and server2026-09-02
Kubek's dungeonsFabric, Forge, NeoForge and Quilt1.21.4 – 26.1.2Server required, client optional2026-04-11
Epic Structures: IglooFabric, Forge, NeoForge and Quilt1.19 – 26.3Server required, client optional2026-07-29

Questions

Does Underground Worlds need Fabric API?

Yes, on Fabric it requires Fabric API. On Forge and NeoForge it requires Forge Config API Port instead.

Why do some biomes not generate with other world generation mods?

The author notes that TerraBlender or Lithostitched may be needed for the biomes to generate alongside other world generation mods.

Can the server run the mod without clients?

No. The server and every player need the mod installed.

In the catalog

Underground Worlds is one of 8,515 World generation mods on ModsFinder, and one of 4,027 World generation mods for Fabric. 13,894 mods support Minecraft 26.2.

World generation mods8,515Fabric modsMods for 26.213,894

More from HexagonNico

All projects
Phantom Loader1.19.4 – 1.20.4Spider Caves1.19.4 – 1.20.4Controlled Insomnia1.21.1 – 1.21.10Reworked Metals1.16.5 – 1.17.1

Similar mods

Biomes O' Plenty1.7.10 – 26.3Cobblemon1.19.2 – 1.21.1Terralith1.18.2 – 26.3YUNG's Better Nether Fortresses1.18.2 – 26.1.2Dungeons and Taverns1.19 – 26.3Yeetus Experimentus1.18.2 – 26.3

What the author says

Underground Worlds is a Minecraft mod that adds underground biomes and underground dungeons, as well as some above ground structures, in a modular and configurable way. Underground Worlds was born as Underground Jungle, a mod that added an underground jungle biome and a jungle temple somewhat inspired by the one in…
HexagonNico, on the Modrinth page

Official listing

Owner
HexagonNico
Published
2023-10-01
Updated on Modrinth
2026-09-02
Facts verified
2026-10-15

Tags

AdventureEquipmentWorld generationDecorationMobsStorage
Open on ModrinthCompare