You need to import it into the pal park
You have to get the National Pokedex and go past the battle tower and on your way there you will find a cave with Groundon in it.
You can't Find Him on Pearl he can be traded from Heart Gold or Soul Silver but you can't catch groundon on Pokemon pearl i hope i helped. :)
Actually despite what the not so smart anonymous said you can find Groudon in Pokemon Pearl but you need to transfer it into the pal park.
You can't get him.you have to catch him from palpark or trade from Pokemon soul silver
You Cannot Catch Groundon In This game The Only Way To Obtain It Is By, Mirgating From Gen 3 Series or By Trading Someone That has It Already.
you find groundon in the embedded tower near the safari zone but you have to get the red orb from mr. Pokemon (blue orb for kyogroe in heartgold)!
i think its charizard (if choose) kyogre,groundon or rayquaza and dialga or palkia from dimond or pearl
In Pokemon Emerald, Groundon and Kyogre are legendary Pokemon. You can find them in the Marine Cave and the Terra Cave.
If you have Pokemon heartgold, you cannot get groundon unless you trade with someone who caught a groundon on soul silver. PS- It has to be from the embedded tower, any migrated groundon will not work.
you do not find dialga in Pokemon pearl
talk to everyone in the whole game to get a groundon.
I am sorry you can't but you can get Kyore. To get groundon you need to trade