You go to fight your dad as the 5th gym leader in Petalburg city. This happens after you beat the first 4 gym leaders.
BRAG!
beat your dad and wallys dad will give it to you.
At new mauville after you beat your dad go to wattson and he'll give you directions
beat the fifth gym, talk to Wally's dad in the house next to the gym
first you beat nolan,your dad, and you go to the building next of the gym and talk to the man. he will give you surf.
* you get to fight your dad after you beat flannery the 4th gym leader. I'd ready with alot of water types trust it took me forever to beat cuz i had no water types and grovyle was my stater i'd be
In total, you must beat four gym leaders before you can face your dad: Roxanne, Brawly, Watson and Flannery.
Beat your gymleader dad in petalburg city. Then go to Wally's uncle's house and talk to uncle, he Will give surf
after you beat steven you go home and your dad says mr. brieny brought the ticket for you
After you beat flannery in lavaridge town go back to petalburg city and battle ur dad at the gym.
You have to go to Wally's parent next door and get HM 03(Surf).
In the gym.