you can't
You use an action replay.
You can catch giratina without any use of action replay in pearl.
You can catch Lugia at Navel Rock.
There is unfortunately no way to catch shadow Pokemon using a commercial cartridge or Action Replay. Sorry!
it has to be traded over or linked or by using a action replay
you go to relic castle
You can't catch Arceus in Pokemon SoulSilver. You can only get it by obtaining it at a Nintendo event, or by using an Action Replay.
No, there is no legitimate Action Replay code for Mewthree for Pokemon Diamond.
You can only find it using an item you get from a Nintendo Event or using Action Replay.
The only way do do that is by using Action Replay this is a lie
using get all the Pokemon on your pokedex code.this anwswer stinks because he said whithout action replay!! go to a Pokemon event. - imaier
migrate it from leaf green or fire red