Things You'll Need
Instructions
Play "Pokemon Ruby" on one Game Boy Advance. Go to Route 117 and look for Roselia in the grassy patches. You have a 30-percent chance of encountering Roselia on this route. Roselia will be Level 13 to Level 14, so have a Pokemon that is similarly leveled to weaken it. Go to the in-game menu and save your game.
Insert "Pokemon Emerald" into a second Game Boy Advance. Connect the this GBA with the GBA that is playing "Pokemon Ruby." Power on both handheld devices. In both games, make sure you have two Pokemon in your party.
Fly to any Hoenn PokeCenter in "Pokemon Emerald" and "Pokemon Ruby." Take the escalator to the left in both games. Speak to the second woman to go to the Pokemon Cable Club Trade Center in "Emerald" and "Ruby."
Trade Roselia from "Ruby" to "Emerald" in the Pokemon Cable Club Trade Center room. In "Pokemon Emerald," choose to trade any Pokemon you have.
Select "Cancel" in one game after the trade to leave the Pokemon Cable Club Trade Center. Your characters will exit the room in both games. Check your party in "Emerald" and you will have Roselia.