You trade seadra holding an item called dragonscale you can get dragonscale in Ruby Sapphire and Emerald
Seadra can be evolved into Kingdra by using a water stone
Seadra can be evolved at any point in the game; to evolve it into a Kingdra, you must first get a Dragon Scale and give it to him/her. Then you must trade it and voila, your Kingdra.
Seadra evolves into Kingdra at level 45.
Catch a horsea or seadra and put the item on seadra (evolve horsea) trade it with someone else and seadra will evolve into kingdra
Seadra evolves when you trade him while he is holding a King's Rock.
Yes, but seadra must be holding a dragon scale.
You have to give the Seadra a Dragon Scale then trade it (and back) and it will evolve into a Kingdra.
Seadra does not evolve into Seaking. Ever. Period.
If you mean Horsea evolves into Seadra its at level 32, but if Kingdra is what you are looking for you need to trade seadra while holding dragon scale.
Seadra learns hydro pump at level 40.
Seadra will evolve when you trade it while it holds the item Dragon Scale.
Yes, by trading a Seadra equipped with a dragon scale.