After the 7th gym, surf around and when you see dark spots in the water, press A and use Dive. Then find a huge block with no wild grass, enter a cave door underwater, then go back up. You should be in Sootopolis City (water is light blue there) the gym leader there is Juan, who specializes in Water Types.
Chat with our AI personalities
fortree
at the gym
pryce the ice type gym leader
slate port does not have a gym
fire