Open full map of Grand Underground, and look for red dot.
Full map can be accessed by hitting Y button:
On full map there are various markers:
- Glowing red dot with red circle around, that moves together with you, is your location
- Small dark red dot is your base
- Orange dots are mining spots
- Blue dots, which tend to move, are other players
All markers are also visible on mini-map, which can be changed from local to full view by clicking right stick, but hunting for one red pixel in colorful mosaic does not sound very easy.
If you want to go to another section of underground you must return to Overworld (Go up in Y menu) and dig down from another place.
Here's a handy list of spots from which you can reach different sections:
- Largest section is almost everywhere, eg. Hearthome town
- Central section: Celestic town
- North-west section: Snowpoint town
- North-east section: Fight area (post game content)
- South-east section: Beach between Pastoria (fly there, walk east) and Sunyshore towns. Narrow piece of shore allows you to reach that section without surfing to islands south of beach.
- South-west section: Sandgem town (starting area)