When you trade it holding a dragon scale.
Because it has to be on Pokemon Diamond,pearl or Plainum.
catch a horsea evolve it into seadra give it a dragon scale and trade it
Seadra does not evolve into Seaking. Ever. Period.
You can evolve Seadra by giving it a Dragon Scale and then trade it. Seadra will then evolve into Kingdra.
Seadra will evolve when you trade it while it holds the item Dragon Scale.
seadra
Seadra can never level up to evolve. You have to trade it when it is holding a Dragon Scale item. - Pokemon Guru
Seadra will only evolve during a trade while it holds dragon scale.
During trade it must hold dragon scale to evolve.
never
Just trade the Seadra while it's holding a Dragon Scale. It'll evolve into Kingdra.
Yes, by trading a Seadra equipped with a dragon scale.