Catching Latios or Latias without using masterball!
First, catch a Pokemon that uses Arena Trap or Shadow Tag. I used Wobbuffet. Your mother will let you choose between red and blue. Blue is Latios and Red is Latias. The one you chose will appear ONLY in the patch near the Safari Zone OR near the surfing area of New Mauville. It is the only area where you can see one of them. Brind lots of ultraballs and timerballs. First, use the ultra so the timer will have the power. Enjoy using the Masterball on ANY pokemon.
Rate this please.
More tricks, tips and cheats for this game are right here - Pokemon Emerald cheats