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