Here's why:
* Generation V (Black & White) introduced new movement mechanics: Instead of relying on HMs, Pokemon Black and White utilized the "Fly" and "Dive" abilities, replacing the need for Surf.
* Surf was reintroduced in Generation VI (X & Y): If you're looking to use Surf in your journey, you'll have to progress to Pokemon X or Y.
To travel on water in Pokemon Black and White, you'll need to:
1. Reach a certain point in the story: After a specific point in the story, you'll be able to use "Dive" with a compatible Pokemon.
2. Dive with a Pokemon: Some Pokemon, like the Water-type Pokemon, can learn Dive. This allows them to dive underwater and swim, letting you access new areas.
Let me know if you have other questions about Pokemon Black and White or any other Pokemon game!