You cannot except by hacking the game. The only game to have a legitimate way to catch a wild Mew programmed into it is Pokémon Emerald Version. With the Old Sea Chart item obtainable only through events, you can access Faraway Island, where a Level 30 Mew resides.
...I may as well add that it's a continuation of the story told in the Pokémon Mansion on Cinnabar Island; after Mewtwo's rampage, the leader of the project, Fuji, took Mew to that island so that it would be safe, leaving behind a message that said "If any human sets foot here again, let it be a kindhearted person. With that hope, I depart."
You cannot catch Mew in "Pokémon Ruby."or you can get mew-two in fire red or leaf green.
no you cant
you can't get mew in leaf green you get it in fire red
gAME sHARK
You Can't you need to trade it from fire red or leaf green
yes......... get a life
You can't get a Mew unless you cheat, I think. A Mewtwo you can only catch in Fire Red\Leaf Green and transfer to your Pearl.
I don't think you can catch MEW without a action replay. But you can catch MEW2 in Pokemon Fire Red or Leaf Green. You CAN'T cach mew without an action replay, but you can trade mew-two from the other games to the newer ones
unfortunatly you caint get mew in platinum butt you can trade it frow leaf green or fire red. or you can use cheats.
how to catch mew in fire red.you have to have all your Pokemon in your party and boxes at level 100 and have beaten the elite 4 100 times then go to cerulean cave and at least have 1 master ball and there you got it a mew in fire red.
no
to catch shiny mew you have to migrate it from Pokemon fire red leaf green from GBA