First you have to defeat him. Then he will ask to join ur team.
You need to beat Darkrai and get Dialga and Palkia to join your team. Go to the place u evolve and wala!
Oh Yes once you beet the game go talk to lapres and she will take you back to the hidden land beat Dialga, and He will ask of he can join Your Team.
just go back to Temporal Tower And beat him and he will join you. His recruitment level is 100% just beat normal dialga. Primal dialga is impossible to get.
after u have defeated primal dialga go and defeat him again and he should ask to join your team
go back to temporal tower after the credits and beat him and he will join i have him now he is lvl 48.
You can't! Only in Pokemon mystery dungeon explorers of time you can! You don't catch them they join your team! Dummy! ^_^
no but after u complete game gio back 2 temporal tower and battle him again he will join your team
You can evolve after you beat darkai and get dialga and palkia on your team ( they join after you beat them the second time.)
After defeating Team Galactic, you can catch Dialga in the Spear Pillar.
You get the credits after defeating Primal dialga. Then you can evolve (not you or your partner yet) your team and get the legendarys to join you after beating them again.
You can't, he sacrifices his life to kill dusknoir when you go and fight dialga. He's dead in other words.
If you mean Explorers of Time/Darkness, go to Temporal Tower, beat Dialga. Then go back and fight it again. Beat it. And tell it to join you. Well yeah pretty much what he said but I would just like to add one thing: No matter what-even if you have the worst luck ever-Dialga will join your team since it is one of those Pokemon that have a 100% recruit rate Have Fun! ;P