Do you have the explorer kit? You need the explorer kit to go underground. You find it in Eterna City.
You must speak with the Underground man in Eterna City. He will then give you an Explorer Kit which will allow you to explore underground and dig for treasures. You can also make a Secret Base underground and connect with friends. Hope I've helped! .:Funkeheap15>.<:.
There is no "entrance" you must get the explorer kit from the digging man in Enterna City (his house is beside the Pokemon center) then just use it outside!
The best way is to use the Explorer kit and dig down there. (You gain it in Eterna City and you will get an explanation).
You get it underground but if you don't have Explorer kit get it in Eterna City
To get the explorer kit in platinum you have to talk to the old man in Eterna City in the house next to the PC.
The Explorer Kit is from Diamond, Pearl and Platinum. It is not in Pokemon Black or White.
Do you have the explorer kit? You need the explorer kit to go underground. You find it in Eterna City.
just use the explorer kit you pile of poo
You need to get the fossil from underground with the explorer kit
no the explorer kit is only exclusive to diamond, pearl and platinum.
you can find them in the mine when you click on the explorer kit
you can get iron plate by using explorer kit
In Enterna city, theres a house south of the Pokemon statue, go in and talk to the old man :D. He will give u the explorer kit.
Underground. Use Explorer Kit, then dig around.
Go under ground using your Explorer Kit
Going underground using the explorer kit that you get in Eterna city and mining.