how do i get mew in pokemon mystery dungeon red for GBA?

1- buy FIANL ISLAND from wigglytuff when you BEAT the game

2- then go through BURIED RELIC and take on the 3 regis on the 15th,,25th,& 35th floor when you beat each regis they'll DROP a part of them pick it up then when you have all 3 parts it'll form a MUSIC BOX(don't use it) now from the 36th floor to the 98th floor MEW will appear just keep a eye on your MESSAGE BOX it'll tell you or not if mew has TRANSFORMED mew can sometimes be right in front or behind you..then after you've gotten mew bring 3 ESCAPE ROPES with you now you can go through the BURIED RELIC again or later when you fight the REGIROCK pick up his part & ESCAPE go through the BURIED RELIC again to fight REGICE pick up his part & ESCAPE last time go through the BURIED RELIC to fight REGISTEEL pick up his part & ESCAPE now that you have all the parts in storage take out 1 part ONLY and put in your bag & go through the BURIED RELIC fight the REGI you picked from the part you took out of storage ROCK = regirock ICE = REGICE,, STEEL = REGISTEEL..NEVER BRING ALL 3 PARTS WITH YOU inside BURIED RELIC because if you do it'll form the MUSIC BOX..glad 2 answer :)

Go to the dungeon Buried Relic. On one of the last 10 floors of the dungeon's 99 floors, mew will be wandering around. Note that he IS NOT a dungeon boss, and instead like a regular pokemon. His recruit rate is extremely low, so he is almost impossible to recruit. You must also have the friend area "Final Island". Good luck!

You can ether trade it with a friend,or buy an action replay..

i recommend an action replay cause you can use that with all your gameboy games,especially pokemon games.