Instructions
Add Pikachu to your group of creatures. You can capture Pikachu by finding a wild one in the tall grass throughout Yellow Forest. When it attacks you, use your current Pokemon to weaken it until you can throw a Pokeball at it and capture it. You can also select Pikachu as your first Pokemon at the beginning of the game.
Develop this Pokemon to levels 14 and 15. At level 14 the Pokemon gains the opportunity to learn how to surf. At level 15, Pikachu has the opportunity to learn how to fly. These abilities are not available until the character reaches these levels.
Search the Blue Lake, Town Outskirts and Winner's Path area of the Johto region to find the Lum Berry. The item appears at random so continue walking and battling wild Pokemon until one drops the berry.
Obtain the Shuca Berry. This item can be found in the Yellow Forest and Stormy Beach areas of the game. The main character's mother will also give it to the player once he helps her with her savings, however this is a random happening and she may give you other items instead.
Give your Pikachu the Lum Berry when it reaches level 14 to give it the surf ability. When it reaches level 15 give it the Shuca Berry to teach it how to fly. Now, your Pikachu will be able to use both of these abilities on command for the rest of the game.