First beat the Mauville Gym leader, Wattson.
Chat with our AI personalities
if you are looking for the new mauville basement then you have to go south of new mauville and find a place to surf in the route between mauville and slateport and you will find it on the right side of the screen
New Mauville MissionMr. Wattson wants you to turn off the big machine at the end of New Mauville by pressing a red button. The cave's full of Electric-type Pokemon and no Trainers.
You can get a magnemite in New Mauville.
From Mauville City, go south, you'll meet the Fisherman. Surf and keep to east. Then, you reach the New Mauville.
You can get it at New Mauville. Also you need to use this HM named Surf.Go through the Cycling Road by using Surf. Then after you get to the Genorator, you turn it off. Then you see a Poke Ball in the East. Then you earned you Thunderstone.