Seafoam islands
To get Seel in Pokemon Emerald you must trade for one from Pokemon FireRed or LeafGreen. Seel can easily be found in the Seafoam Islands on Pokemon FireRed and LeafGreen.
At SEAFOAM ISLANDS. There you can find Pokémon like SEEL and DEWGONG.
Dewgong
you must migrate it from leafgreen or firered
at level 34 seel shoud evolve into dewgong
No Dewgong cannot evolve as it is Seel's final form.
Well it depends on what version your playing if firered you can find seel, magikarp, shellder, zubat, golbat, tentacool, articuno. If your playing leafgreen you won't find shellder instead you will find slowpoke everything else you can catch.
If you go to the Seafoam Island, you can find Seel (Isn't an Ice-Type, but it's evolution Dewgong is), Jynx and of course the most powerful of all, an Articuno in level 50. The only other Ice-Type is Cloyster, but it's pre-evolved form Shellder can only be caught in FireRed. You can also find Seel and also Dewgong I think in the Icefall Cave.
There's no TM dive in pokemon fire red but there is in emerald, saphirre and ruby. But the way is to level up pokemon (seel level 41,dewgong level 45) to get TM dive (in firered).
You can find Seels all the time in the Whirl Islands
Seel is a metallic black color.
You can find Seel on floors 3 through 7 in Mt. Freeze. They are found at around level 18 there.