As many people know, the region of Hoenn is known for having vast amounts of water. As such, you'll be spending a lot of the time surfing from A to B. While the encounter rate has been decreased, this can be quite labourious. As such, there are a few changes to Surf depending on the Pokémon you use.
No special features
Sharpedo moves at twice the speed of normal. You cannot fish while riding Sharpedo
Kyogre moves slightly faster than normal Pokémon and has a much larger hitbox underwater