Nothing has changed since you last left so heal up your Pokemon, prepare your best team and get ready to fight your dad in the City Gym. The Gym specializes in Normal-type Pokemon. The layout of Norman's gym is a bit different. Individual trainers occupy separate rooms depending on the battle item they use. The rooms include One-Hit KO Room, Attack Room, Defense Rom, Speed, Room, Accuracy Room, and Zero Reduction Room.
You can freely enter and leave each room as you please so its possible to fall back, heal, then fight every trainer in every room.
Here are the list of trainers:
(Speed Room)
(Accuracy Room)
(Zero Reduction Room)
(Defense Room)
(Recovery Room)
(One Hit KO Room)
(Strength Room)
No matter what rooms you choose, you'll still end up in Norman's room.
Petalburg Gym Leader Norman (Reward: p3,600)
After defeating Norman, Pokemon up to LV60 will obey you and you can use Surf outside the battle now. You'll also receive TM67 Retaliate. After defeating Norman, he'll see you outside. You'll find Wally there as well. During this conversation, you'll receive HM03 Surf. Norman will then tell you to go beyond Route 118. This time, Wally will take you back to Mauville, in its Route 118 exit.