Can I trade a Houndour/Houndoom from Platinum/HGSS to Diamond/Pearl?

Question

Assuming I have both versions of the game with two DS.
Diamond or Pearl in Eterna City with no National Dex and only 1badge.
Meanwhile Platinum with 3rd badge and access to Route 214.
Can I catch a Houndour in Route 214 or Valor Lakefront on my Platinum and trade it to Diamond/Pearl?
And catch Houndour in HGSS route 7 and same Diamond/Pearl conditions?

Answer 1

Yes

You can trade Pokemon between any two Generation IV games, as they are all compatible. To trade between these games, you only need to meet two requirements:

• In Diamond, Pearl, and Platinum, you need to have obtained the pokedex from Professor Rowan. In Heartgold and Soulsilver, you need to have obtained the pokedex from Professor Oak.

• In all Generation IV games, you need to have at least two Pokemon in your party.

It's as simple as that. You've already obtained the pokedex for Diamond, Pearl, and Platinum, so as long as you have at least two Pokemon in each of these games, you should be able to trade between them. The same is true for HG/SS.

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Happy trading!