Things You'll Need
Instructions
Plug the "Pokemon" game into the top of the GameShark. Plug the GameShark into the Game Boy. Flip the switch at the top of the Game Boy to turn it on.
Press "Add GameShark Code" when prompted.
Add the code "E7343B1C-1E9465D8 03C39BA2-B0541E66 85DC5BF3-76315A10" if you're playing "Pokemon Sapphire" or "Pokemon Ruby." If you're playing "Pokemon Emerald," add the code "CBDAAE69BFD5 8B4DD03454A1 533A3DB37FD9 EC4ABD5C4B38 8F76DA15170C 64A2B94C6BE1 DF9836061585 FC0E4912436A DF9836061585." If you're playing "Pokemon FireRed" or "Pokemon LeafGreen," add the code "4202462CFFFF 0000003C0002 42025BA0FFFF 0000001A0002 42028FC0FFFF 0000001A0002." Press "Done" when you're finished. You will be taken back to the main menu of the GameShark.
Select "Start Game With Codes." from the GameShark menu.
Press the "Start" button after the game loads, then select "PokeDex." Latios will now be listed as "Found."