How do you get Giratina in pokemon daimond?

Answer 1

you can get giratina only in explorers of time/darkness or sky. (obviously)

its a wonder mail dungeon, so you can look up the code online or you can receive it from your ds with Nintendo wi fi connection*, the dungeon is call World Abyss and it has 50+ floors, when you reach the end of the dungeon you will fight giratina, upon defeating it you gain an item that makes Pokemon easier to recruit and if your leader is you(your starter Pokemon) giratina will offer to join your team when the battle is over.

*to receve these missions you must have rescued sizor after you have beaten the game

Answer 2

After you've defeated the Elite Four, you will notice a new path off Route 205 (south of Floroama Town) called Spring Path. Go down Spring Path to Sendoff Spring, where you will see a cave entrance.

Go through the cave entrance, which is the entrance to Turnback Cave. In Tunback Cave is Giratina. Turnback Cave is pretty much my favourite cave in any Pokemon game because, as it is of a random quality, you will always end up at Giratina. What worked for me was basically go through the door on the right every time, but you can go through whichever door you want. But, whatever you do DO NOT exit a room through the same door as you entered...or you'll end up at the cave entrance.