Things You'll Need
Instructions
Catching Latios
Restore power to the Power Plant by obtaining the Machine Part from the Cerulean City Gym after defeating the Team Rocket agent who stole it on Nugget Bridge. Bring it back to the Power Plant.
Go next to Saffron City and speak to the Copycat Girl who lost her Clefairy Doll. Go to Vermillion City and obtain the Clefairy Doll from one of the people inside the Pokemon Fan Club. After you exit the building, Steven will tell you that the legendary Latios has been spotted. This triggers the appearance of Latios in the fields of Kanto.
Obtain a Wobbuffet, as its Shadow Tag ability will prevent Latios from fleeing battle. Raise it to level 40 and keep it at the top of your party. Obtain some Repels, Super Repels, or Max Repels (at least a dozen). Save the game.
Go to any grassy field and use the Repel spray. Because the first Pokemon in your party is level 40, only level 40 or higher Pokemon will attack you, such as the level 40 Latios. Run or bike around the grass until the Repel wears off, then repeat with another grassy route until you find Latios. Stock up on more Repel spray if necessary.
Use Wobbuffet's Mirror Coat to reflect Latios's Dragonbreath and Luster Purge back at it until it is low on HP. This move is risky, as it may knock out the Pokemon, but it will reappear after defeating the Champion. You can also reset the game if you make Latios faint. Use Fast Balls to try to capture Latios, and use Ultra Balls if you run out.
Use the Master Ball if you are willing to part with it. This will save you from having to capture and train a Wobbuffet to level 40. It will also eliminate the risk of accidentally making Latios faint in battle.
Catching Latias
Enter the following Action Replay code if you do not have an Enigma Stone from the July-August 2010 giveaway:
94000130 FCFF0000
62111880 00000000
B2111880 00000000
20009E4C 00000003
10009E50 00000218
D2000000 00000000
Enter the game and press the "L" and "R" buttons simultaneously to activate the cheat.
Go to any Pokemart and speak to the green Mystery Gift man, who will give you an Enigma Stone. Save the game.
Take the Enigma Stone to the Pewter City museum and speak to Steven and the scientist. When you leave the museum, a wild Latias will be waiting right outside to battle you. Capture it normally, as this Latias will not flee from battle. If you accidentally make it faint, reset the game and try again.