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