After you beat Norman he will tell you to go to Walley's house, next door, and his parents will give it to you.
The most easiest way to get a Pokemon that can surf is get a Zizagoon,it can learn surf.
Surf to an island
Surf Right of Lilycove
Any water Pokemon besides magikarp and also linoone can learn surf as well.
Try to surf you may find it
surf
hach an egg or surf
You have to surf from LILYCOVE city to the right
You have to surf from either Mossdeep or Sootopolis.
He Doesnt.
You get surf for beating your dads gym.
Swampert, Hariyama, and Ludicolo.