You have to put a Dewgong in the Pokemon Daycare in Solaceon Town with a Ditto or another Pokemon in the same breeding group and walk until they tell you that they found an egg. Then you can hatch the Seel by walking 5,355 steps, or you could have a Pokemon in your party with the Ability Flame Body to cut the number of steps in half.
Pokemon that have Flame Body: Slugma, Magcargo, Magby, Magmar, and Magmortar.
You can get a Seel in Pokemon Pearl by finding it in the water on route 226.
Migrate or Trade. Seel is NOT in Pearl.
The same Pokemon you find in Diamond and Pearl. Tentacruel, Magikarp, Golduck, Psyduck, Seaking, Goldeen, Seel, Dewdong, and rarely for me Gyarados. But their are much more than just that. Thanks for letting me answer your question!
In Pokemon Diamond, you can get Dialga, Seel, Scyther, Murkrow, Scizor, Larvitar, Poochyena, Aron, Kecleon, Cranidos, and Stunky. Those aren't in Pearl. Pearl has Palkia, Slowpoke, Pinsir, Misdreavus, Houndour, Stantler, Spheal, Bagon, Sheildon, and Glameow, though.
i believe you get it in veilstone or sunnyshore
The Pokemon exclusive to Pokemon Diamond are: Seel, Dewgong, Scyther, Scizor, Murkrow, Honchkrow, Larvitar, Pupitar, Tyranitar, Poochyena, Mightyena, Aron, Lairon, Aggron, Kecleon, Cranidos, Rampardos, Stunky, Skuntank, and Dialga.
Level 34 in PLATINUM
lvl it until it evolves
There are a few places you can find a dewgong in on Pokemon Platinum version. You can find him on Victory road, route 226, and route 230. If you catch a Seel you can also get Dewgong by leveling Seel up to level 34.
the Pokemon you can find in diamond but no pearl are: Seel Dewgong Mr. Mime Scyther Murkrow Larvitar Mightyena Silcoon Aron Kecleon Cranidos Stunky Stunktank Dialga
Diamond-Seel, Dewgong, Mr.Mime, Scyther, Murkrow, Larvitar, Mightyena, Silcoon, Aron, Kecleon, Cranidos, Stunky, Stuntank, Dialga Pearl-Slowpoke, Pinsir, Sudwoodo, Misdreavus, Houndoom, Stantler, Cascoon, Dustox, Spheal, Sealeo, Bagon, Shieldon, Glameow, Purugly, Palkia
Diamond-Seel, Dewgong, Mr.Mime, Scyther, Murkrow, Larvitar, Mightyena, Silcoon, Aron, Kecleon, Cranidos, Stunky, Stuntank, Dialga Pearl-Slowpoke, Pinsir, Sudwoodo, Misdreavus, Houndoom, Stantler, Cascoon, Dustox, Spheal, Sealeo, Bagon, Shieldon, Glameow, Purugly, Palkia