>>58994879If memory serves
There's three between Pacifilog and Slateport, and two between Pacifilog and the greater ocean. One between the greater ocean and Ever Grande.
Then I want to say There's roughly 8 in the big ocean area. Maybe 9.
Then I think there's two between Dewford and Mr. Briney, and three between Dewford and Slateport.
Finally, I believe there is one route that is almost entirely water above Rustburo, west and north of where Meteor Falls spits you out.
So, I think it's roughly 20 routes that are majority water, give or take. Some of these have some other features, but are overwhelmingly water. I'm not even considering routes like the one between Mauville and the route to Fortree, or between the cycling road and route where you first battle may/brendan, despite those being majority water, too, but they're not overwhelming majority water.