Where to Find and Catch Empoleon
From Pokemon Go Wiki
Empoleon are found and captured in Nest and Habitat locations.
Nests
Empoleon Nests are locations that consistently spawn Empoleon.
Habitats
Empoleon Habitats are spawn locations where Empoleon 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: