How do you get Dialga and Palkia?

Answer 1

In Platinum, to get the lustrous orb and adamant orb to summon dialga and palkia, they are both in a little room on top of the only waterfall in mount coronet. After you get them go to celestic town and go into the little cave were u first battled Cyrus and press 'A' on the drawings of the three little figures and listen to cynthias little talk.then talk to her grandmother (she is in the house on the top of the city). once you've done this go to the top of mount coronet and interact with the portals.

credit: GameFaqs

Get to the top of mt. cornet after beating Cyrus at the Team Galactic head quarters and beat Jupiter and Mars. After u beat them with your rival then go to Cyrus beat him and catch Palkia with the master ball right when Palkia comes up and there u go u have Palkia.

-edit-

when you say AND palkia, it's impossible to get dialga AND palkia in ONE game card. The only* way to get BOTH of those pokemons is do what the above says in both Pokemon diamond AND pearl. (Diamond; Dialga | Pearl; Palkia) Then, just trade the pokemon to get both of those Pokemon in one game card.Who wants Dialga and Palkia!?If you do this is how you get them.You will need to fly to Oreburgh City and go north.Then go into the cave that leads to Mt. Corenet. Make sure you have repels,and Rock Climb and go to spear pillar.If not both Dialga or Palkia are not in spear pillar wait about a week until the next.If none of them are in spear pillar wait about a week.In pearl and diamond Dialga and Palkia are LV 48 and in platinum they are LV 70.I hope you catch them! Good luck!;)