You can't get them in Pokemon diamond, you must trade from Pokemon emerald.
there is no way sorry
you have to trade it from a different game, trying ctahing it on Pokemon emerald and migrate it to Pokemon diamond
Trade to emerald and migrate them
You can't unless you trade it from diamond
no, i think you have to trade it from the hoenn region(pokemon emerald) to get it in your diamond game
YUP
You can't get the Regi's in Pokemon Diamond And Pearl. You have to trade from Pokemon Ruby, Sapphire, and Emerald.
Transfer it from emerald OR trade it from soul silver or heart gold
Pokemon Emerald can trade with Pokemon versions ruby and sapphire through the use of a trade cable. Emerald can use Wireless adapters to trade with FireRed and LeafGreen aswell. Pokemon from emerald can be permanantly traded to Pokemon games Platinum, Pearl and Diamond by using the GBA slot.. =D I hope this helps =D
You can trade it from Pokemon Emerald. In Pokemon Emerald, when you find Rayquaza, there is a small chance that it is shiny when you find it. Save the game right before you fight him and keep trying until it turns black. Then catch it and trade it to Pokemon Diamond.
trade it over from emerald or ruby and Sapphire