through a Nintendo special event. unfortunatly they don't do them for that anymore.
I'm not all that sure about how you get it.(problabe an event)But if you get to the island you climb a hill and belive it or not YOU WILL FIND A MEW IN EMERALD!!!!
YOU COULD RECRUIT IT EASIER BY MIXING RECORDS WITH SOMEONE WHO HAS DONE THE NINTENDO EVENT AND YOU'LL ATOMATICALLY GET THE ARORA TICKET.
to find deoxys , you have to get an arora ticket and go to the island
its not an emerald its RAYQUAZA the main legendary Pokemon in Pokemon emerald.
you need an arora ticket from a Pokemon event
You cannot get a Yanma in Pokemon Emerald, as only Hoenn Region Pokemon can be found in Pokemon Emerald.
There is no PalPark in Pokemon Emerald.
Sinnoh Pokemon DO NOT EXIST IN EMERALD!!!
There is no Autosave in Pokemon Emerald.
where can i find groudan in Pokemon emerald
defog is not in emerald,