In sapphire, the 5th gym leader is your dad, in that city after Oakdale.
The fifth gym is in petalburg city
The 8th Gym Leader in Pokémon Sapphire can be found in Sootopolis City.
Sotololips City
in the gym in petalburg city
it is in mauville city it is in mauville city
The third gym leader in Pokemon Sapphire is Wattson and he is located in Mauville City.
mauville city gym leader wattson
Slateport City doesn't have a gym.
MOSSDEEP CITY
Mossdeep City
Peatlburg city