Question

I want to know if Pokemon in fire red could be trade to the Pokemon in emerald version?

Answer 1

Answering because there's a little more than the National Dex is needed.

• Get the National Pokedex in both games.
• In FireRed, talk to Celio in One Island's Pokemon Center. He will acknowledge that you have caught lots of Pokemon and say he's looking for 2 Gems. You need to give Celio both the Ruby and Sapphire.
• The Ruby is located at Mt. Ember. When you start to ascend the mountain, you should see Rocket Grunts. Talk to them, beat them up, and go inside the cave they were blocking and get the Ruby. Give the Ruby to Celio and he will give you the Rainbow Pass to get to Four, Five, Six, and Seven Islands.
• The Sapphire is located in Four Island's Icefall Cave. Defeat the Rockets and approach the Sapphire. A scientist steals it from you and you need to chase him to Six Island's Rocket Hideout to find him. After navigating the hideout's warp panels, getting the Sapphire, go to One Island and give the Sapphire to Celio. Now you can trade.

Answer 2

Yes since they are both Generation 3 games you can trade between the two. But you need the National Dex in Firered/Leafgreen.

Answer 3

According to Serebii, you can, but you need the National Dex in FireRed.