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