How to Build an Underground Base in Minecraft

Guide Java Bedrock

Quick answer: Underground base plan: dig a stairwell to Y=10-20, hollow out a main hall (11x11 or bigger) with a 5-block ceiling, then branch into rooms - storage, enchanting, farms, bedroom. Light everything, and hide the entrance.

What you need

Pickaxes - several (a good Efficiency one saves hours)
Torches, lots
Support beams: logs or pillars every 5-6 blocks
Flooring and wall blocks of your theme

Step by step

Depth: Y=10 to Y=20 is ideal - below the caves and the noise, above the deep lava and the deep dark.
Entrance: a staircase (straight 1x2 or spiral) from your house or a hidden entrance - waterfall, trapdoor or painting door.
Main hall first: an 11x11 room with a 5-block-high ceiling. Every other room branches off this hub.
Rooms to add: storage with an item sorter, enchanting with 15 bookshelves, a bedroom, a nether portal room (behind a door - portals are loud), a smelting room.
Underground farms: wheat and carrots grow fine with lanterns; tree farms need 8+ block ceilings; animals need grass floors.
Structure: pillars or log beams every 5-6 blocks keep big rooms from looking like caves and mark where to light.
Theme the walls: full stone brick for a bunker, stripped logs for a hobbit hole, quartz for a lab. Bare cave walls read as 'unfinished'.
Airflow trick: dig one 1x1 chimney shaft to the surface with glass on top - daylight down the middle of your hall.
Mob-proofing: light every corner as you dig - a base you excavate dark will spawn guests.

Java vs Bedrock

Identical on Java and Bedrock.

Versions: Digging and lighting rules are the same in every current version.

Frequently asked questions

How do I find my base again without coordinates?

Build the entrance inside or beside your surface house, and mark the spot with a distinctive tower or path. Or write down the F3 coordinates once.

Are underground bases safe from raids?

From other players, mostly - nobody sees a hill. From mobs, only if you light it: darkness underground spawns them inside your walls.