Things You'll Need
Instructions
Insert the Action Replay device into the GameBoy Advance if you do not yet have a Mystic Ticket. Insert the "Pokemon Emerald" game into the slot in the Action Replay. Turn the Game Boy Advance on. The Action Replay games list will load.
Use the "Down" button to scroll to "Pokemon Emerald" in the Action Replay games list. Select "New Code." When prompted, name the code "Mystic Ticket." Then, in the space provided, enter "BE39B3A8 280987E1." Save the code, which will put the Mystic Ticket into your in-game PC.
Make another new code. Name this code "Naval Rock Enabler." Enter the code "E961B0C7 750B1250" and then save it. (If you do not enter this code, you won't be able to use the Mystic Ticket.)
Start the game. Go to a Pokemon Center and open your inventory, stored in the PC. Select the Mystic Ticket, then leave the Pokemon Center.
Go to the docks of Lilycove City or Slateport City. To find Lilycove City, travel southeast from Fortree Town on Route 120 and then Route 121. To get to Slateport City, travel south from Mauville City on Route 110 or east from Oldale Town on Route 103. Talk to the captain in front of the ship, and select "Naval Rock" from his destination list to travel there.
Go down to the lowest floor to capture Lugia and climb to the highest floor to get Ho-Oh. Return to the ship to go back to the mainland when you are done.