Veronne region of the Pokemon world. My region map. This isn't the whole region however. Just the largest land of the islands. The weird green blob at the bottom is an underwater island landmass. the deep blue is areas you can use surf and dive while the light blue is areas you can just surf.

There are different levels of diving though and you need different items when you do. Shallow dive-snorkel. Deep dive-scuba suit, air tank, pressure rugulator, and temperature regulator.

You will use both regulators when you are hiking high in the mountains and using Skyride HM as well. If you have a Pokemon with Pressure ability you do not need the Pressure regulator.

The Temp regulator will also be used with the heatproof suit which allows you dives into magma pools and to survive the heat in lavatubes. The regulators get worn out after so many uses so it's cheaper to find Pokemon with natural abilities that can protect you instead.

You will start your journey at the town at the top- Seedlink Town and make a round trip back at which point the small airport will be open and ready to fly you to the next island-as the waters between this and the next island are strong, rapid currents.