Instructions
Place Lugia and five other Pokemon into your Pokemon Storage System in "Pokemon Sapphire," "Pokemon Ruby," "Pokemon Emerald," "Pokemon FireRed" or "Pokemon LeafGreen." Insert the GBA Game Pak and the Nintendo DS cartridge into your Nintendo DS.
Use the switch to power on your Nintendo DS. Select the "Pokemon Pearl" or "Pokemon Diamond" icon on the main menu. Press any button to skip to the title screen. Push the "A" button to go the start menu. Choose "Migrate from GBA Game." Select five Pokemon and the Lugia from your Pokemon Storage System.
Launch your saved game. Find Pal Park on Route 221. Enter the building and speak to the man in the dull green outfit. He will explain Pal Park to you. Agree to participate in a Pal Park game. Once you agree, he will give you six Park Balls.
Look for Lugia in the mountainous part of Pal Park. Catch the Legendary Pokemon with a Park Ball. You will catch him on the first try. Capture the other five Pokemon you migrated to end the Pal Park game.
Access your Pokemon Storage System in Pal Park. Look for the Lugia in all of the boxes. Place the Lugia into your party.