Where to Find and Catch Spheal
From Pokemon Go Wiki
Spheal are found and captured in Nest and Habitat locations.
Nests
Spheal Nests are locations that consistently spawn Spheal.
Habitats
Spheal Habitats are spawn locations where Spheal is likely to be encountered, but not guaranteed the way a Nest is.
Additional Tips and Information
Best Nests
If you know a really good nest or any of the nests above is really good, list them here: