You can breed it at the daycare.
Chat with our AI personalities
5,000
Earn enough coins in the game corner and you can get an eevee as a prize for like 1100 coins or something
You have to get it from a friend who has Pearl/Diamond/Platinum
You can't catch them, but Bill gives you one at his house in Goldenrod.
Evolve from Eevee by happiness at day time.(4:00am to 8:pm)