Where can you get Mew without cheating?

Answer 1

mew is only available from Nintendo events, or, from the WIIware game Pokemon ranch

ignore the crossed out but yes in poke ranch transfer 100 Pokemon to the game and the girl will trade hers for a egg or for a certain Pokemon she will give u a mew egg. in platinum after u seen all the Pokemon ( not incudeing mew or mewtwo)go to the road on the way to the champions ( after complet natinol dex) and he should be there. also i havent tested this one but i saw it on a you tube vid my bro posted get a m unkown an e unknown and a w unknow no other Pokemon and then go to the ruins in the town with thepoke day care and go down a flight of stairs after u enter the flight of stairs on the left hand side at the end of the hall run around the rock to get shiney mew ( only works if have natinol dex with all Pokemon {u might have had to seen mew or mew two for this one but idk}) hope my advise was helpful but i will tell u, u don't have to use Nintendo events so ignore that.