Mew is an exulsive Emerald Pokemon after the Red/Blue Versions.
What you need:
A Dark lvl.30 Pokemon (from now on mightyena)
A Pokemon that can sing( from now on swablu)
A weak pokemon at lvl.3 (Just do as I say)
29 Ultra Balls and 10 Timer balls
Old sea map from nintendo events
(saving before mew spots you and having to chase it)
After beating the elite four the S.S.Tidal would be made
So Go to lily cove and show the woman the old sea map the S.S. Tidal will come and take you to Farawy Island
Which looks like a jungle but worth millions of it.
There are National wild pokemon and in the last room...........MEW! but, you wont battle him right away
chase like cat and mouse first and corner and examine it. Mew will not run this tim and show you his power.
Send out your lvl 30 Mightyena and use a bite and don't let the mew faint. withdraw mightyena. then send out the weak pkmn let mew faint it (if it wasn't it then swablu would be it so it would be extremely hard) then sent out swablu and it must be faster than 87 quality with speed and high def/sp.def.Use sing. then mew...might use transform! but he can't coz he is asleep. then use timer balls and if they finished while mew awakened, use sing again be carefull if transform.
then use about 16 ultra balls and...Congratulation mew is yours.Yeah, if some ultra or timer remained, you can catch wild pkmn around here ten you can go back to honnen
Mew lv.30 (Mew is intelligent and can learn any single move)