How can you obtain Dialga in Pokemon Pearl?
first of all, you need to have beaten the Pokemon league and
have the national pokedex.
next, go to survival area and from there make your way to stark
mountain and catch heatran (level 70)
after that, go to spear pillar and please note that you should
have palkia and heatran in your party, and advance through to the
same spot you encountered palkia and there you will then, battle
dialga (please note THIS IS NOT TRUE I TRIED IT AND IT DOESN'T
WORK) you have to trade with someone with diamond or use