Transfer it from Ruby, Sapphire or Emerald using the Pal Park.
You can only get groudon if you migrated it through the pal park from Ruby or Emerald.
groudon is in pal park in the mountain area
There are two ways of getting Groudon on Pokemon Diamond. The First way is trade it with people in the GTS (Global Trade Station). Or you can migrate it from Pokemon Emerald, Ruby, or Sapphire.
In Diamond version you can only get groudon though palpark or by trading with other players. It does not appear naturally in the wild.
There is no real way to get groudon, but you can just migrate it, or have a friend trade it to you.
the only way to get groudon is to either import it from Pokemon sapphire/ ruby/ or emerald, OR, trade it from pearl/diamond/or platinum.
you cant get it without migrating.
sorry you can't unless you cheat
if you have action replay you will get to pick a pokemon so groudon is a hard pokemon you need the red orb for groudon on pokemon soul silver version or pokemon heart gold version but use action replay on pokemon pearl,diamond,platinum
Groudon does not appear naturally within the game. Transfer it from Diamond pearl platinum soulsilver or heartgold.
There are two ways of getting Groudon on Pokemon Diamond. The First way is trade it with people in the GTS (Global Trade Station). Or you can migrate it from Pokemon Emerald, Ruby, or Sapphire.
The coolest thing about Pokemon Diamond is catching all the rare Pokemon. I have uxie, alzef, giratina, dialga, sceptile, and groudon! This is Denabaker9, contact me for details!