Surf is HM #3. :-)
you get from alder at twist mountain.
Get the HM Surf then teach it to a pokemon.
one of the gym leaders give you it
You get HM Surf and surf there
you need to find the hm for surf but you can only use it when you beat the gym leader pryce.
You need a water Pokemon and the surf HM
U can find the hm Surf in the solar cave at the 20th floor, u don't have to need a key, but u've to need a pokémon that flies over the ground or a water pokémon to take the item, bcz the hm surf is surrounder by water.
In the safari zone at fuchsia city.
You find it in the Giant Chasm. You need the HM Surf to get there.
You can get surf in Pokemon black and white by battling Cheren at the Twisted Mountain. Then Champion Alder will give both you can Cheren th HM Surf.
The HM surf allows you to surf across water. You can find it in the Safari Zone in the Secret House.