What Pokemon games can trade with Pokemon emerald?

Answer 1

Ruby, sapphire, another emerald or firered and leafgreen. Must have national dex for all games and for firered and leafgreen you need to get the ruby and sapphire and give it to celio on one island.

Answer 2

Only between other Hoenn games but after defeating the elite 4 you can trade to and from Kanto if the Kanto game has finished the after game.