How to Catch Emerald Deoxys Without Cheats in "Pokemon"by Ann LaPan ; Updated September 22, 2017
Deoxys is a strong legendary or mythical Pokemon. Although it does not evolve from or into any other Pokemon, it can change form. Each of its forms has a different appearance, although it retains the same red and blue colors. Each form also has a different amount of strength, speed, attack or defense. Deoxys can be found in several of the Pokemon games, including "Pokemon Emerald." The steps to catch Deoxys in "Pokemon Emerald" are the same as for "Pokemon LeafGreen" or "Pokemon FireRed."
Walk inside any Pokemart throughout the game. A Pokemart is a store that can be found in all of the towns in the game.
Look at the questionnaire on the counter inside the store. Answer the questionnaire by typing in "Link Together With All." The storekeeper will then speak to you. He will give you access to the Mystery Gift system.
Access the Mystery Gift system. The Mystery Gift system is located on the startup menu, so you will need to save and shut off the game, then turn it back on. Once you’re in the Mystery Gift system, choose the Wonder Gift.
Enter any Pokemon center. These are rest areas located in all the towns in the game. Talk to the man in the Pokemon center with the green hat. This man will give you the Aurora ticket.
Buy several Ultra Balls at a Pokemart. You’ll use these to catch Deoxys. Select several of your strong Pokemon, levels 30 or 40, to put in your party. Deoxys is strong, so you’ll need strong Pokemon to fight it.
Use the Aurora ticket in Vermillion City. The boat you ride there will bring you to Birth Island.
Save the game once you get to Birth Island. This way, if you don’t capture Deoxys, you can simply shut the game off and try again, without losing any other important data.
Solve the triangular puzzle one the island. You can use your own puzzle-solving skills to do this, or check with a walkthrough online. Once you’ve solved the puzzle, Deoxys will appear.
Battle Deoxys. Don’t attempt to knock it out. Rather, battle it until its Hit Points are minimal. Then throw an Ultra Ball. If the Hit Points are low enough, you’ll capture it. Keep throwing balls until Deoxys is captured.