You can't join
You may not join Team Galactic in Pokemon Pearl or Diamond.
No, you cannot join Team Galactic in any of the official Pokemon games.
No.
Go to the Pokemon spa there for 365 days in a row. On the 364 day Commander Saturn will be there and ask you to join team galactic!
I don't think you can join team galactic and if you can, I'm giving you bad advice! I don't think you can join team galactic!
You can't join team rocket in Pokemon diamond. Actually team rocket is not on the game
You can't.
you can't
It is easy you enable walk through walls code and you go to galactic eternal building and talk to people.
You can't
you have to go to sunyshore city and go in the house that is next to the 1 that has a board and go in the house next to it and go in it and talk to the old people everyday and Cyrus will appear
There's no such thing as "team team galactic". If you think you can join Team Galactic, you can't. The only Game where you play as a semi-bad guy is Colosseum.