How do you get Dialga on plantinum?

Answer 1

After you catch giratina,I'm pretty sure there will be two ovals,one pink and one blue,the blue oval contains dialga and the pink one contains palkia you need the adamant and lustrous orb if you have them click on the oval and they will show up!

Answer 2

You go to the spear pillar, but in the part where there is an ocean in a cave, surf through the ocean. At the end of the ocean, there is a cave. GO INTO THE CAVE AND GET THE TWO ITEMS IN THERE. Then you go to the spear pillar, and there will be a blue portal. Push A and it will be Dialga. I recommend Ultra Balls! After you catch it go into the cave behind spear pillar, and go into Spear Pillar again and there will be a pink portal. Click A and it will be Palkia. Again, Ultra balls!

Answer 3

In Pokemon platinum version, you catch Dialga and Palkia in the spear pillar.