Talk:Walkthrough/@comment-209.74.126.84-20140405033838/@comment-24716159-20140405073132

You know the cave that you used to get to the city with the 8th gym (the entrance is at the end of route 317). Go to that cave, and use surf on the water. Swim out to the area of the water that is much darker than the rest and use Dive (it's an HM that you can get in Caspian City). Then just move on from there, you can use dive to swim both up and down.