The city that surf is located in on the Pokemon Emerald game is Bade. In order to obtain this ability one needs to first retrieve the five badge and then visit the gym in Bade. Once in Bade players need to find the gym and the house located next to the gym. Enter into the house and speak to Wally's father who will provide the surf ability.
First you need a Pokemon that knows surf. Then surf all the way up from Rusboro City to an island, not the one where battle girl is located.
look in mossdeep city
Surf south until you can't surf no more, then surf west to Pacifidog.
by using fly or surf
Mosdeep City Surf there from Lilycove
surf surf surf.
right before you get to the Pokemon league on safire, ruby, or emerald you surf or fish and you will get one
Surf to Evergrand city through the victory road and defeat the Pokemon league
you go to Petalburg city gym to get your fourth bage and surf
Surf from Mossdeep City to Ever Grande City, then get past victory road.
the elite four is in ever grande city you will need waterfall to get there and surf.
surf off of lily cove city go up and its in a cave