You can't, you can only get the three regi's in Pokémon Platinum with the lvl 100 event REGIGAS.
trade them
I believe their isn't a code you can't get the regi's in Pokemon pearl unless you trade.
Trade someone with Ruby,Sapphire,and Emerald.
u cant caught the regis in Pokemon pearl if you want the regis migrate it from sapphire,ruby or emerald
It is only possible by cheating.Not by regular gameplay.
You must Migrate from Sapphire, Ruby or Emrald.
On Pokemon platinum, diamond, and pearl you have to get regirock, registeel, and regiice then you go to the snowpoint temple and go to the end and regigigass will be there talk to him and he will battle you.(you HAVE TO have the three regis- with you. on all the other ones you cant but you can get the three regi. forgot to get the three regis n platinum and diamond and pearl you have to migrate them. Hoped this helps!
I think you have to transfer the three regis from platinum version to pearl version but you have to have platinum version I think that's all I know
you can't catch any of the three regis on any DS game except platnium.sorry:(
Margaret Regis has written: 'The Attack on Pearl Harbor'
Event or Trade.
you cant get the three regi's in heart gold or soul silver. You can only get them in Pearl, Diamond and Platnium