at the beginning when u chose your Pokemon or you can use a code
Actually, you don't have to catch oshawott you can get it as a starter in pokemon black and white. Starters: Tepig Snivy or Oshawott.
Nope only by trade or breeding.
No, but if you have a Ditto, and others have an evolution of Oshawott (Oshawott, Dewott, or Samurott), then you could trade a pokemon for that evolution of Oshawott. Then you must leave Ditto and the evolution of Oshawott in the daycare together for a while. Then talk to the day care man and he will give you the Oshawott egg.
Oshawott
oshawott!
A female of the Oshawott line and any member of the Field egg group, or any Oshawott line member and a Ditto.
oshawott snivy tepig
Oshawott.
Like most starter Pokemon, Oshawott evolves at level 16 into Dewott and then into Samurott at level 36
it evolves at level 64 into a hydreigon
Oshawott
The first Pokemon is Snivy, Tepig. Oshawott.