What do you need to dive in Pokemon white?

You don't need anything special to "dive" in Pokemon White. The game doesn't have a diving mechanic. Perhaps you're thinking of a different aspect of the game?

Could you clarify what you mean by "dive"? Here are some possibilities:

* Do you mean swimming? You can use the HM Surf to travel across bodies of water.

* Are you thinking of a specific move or item? There are moves like Dive and items like the Dive Ball that are used in other Pokemon games, but not in Pokemon White.

* Maybe you're thinking of a specific area in the game? There are underwater areas like the Seafoam Islands in other games, but these don't exist in Pokemon White.

Please provide more context so I can help you!