I didn’t get a chance to go to all of the amazing stores in Copenhagen (there are just that many!), but here are a few I did get to rummage around in. Overall, I would say the quality of secondhand pieces in Copenhagen is exceptional.
Episode - similar to Rokit in London
Times up - all pre-loved designer, lots of Missoni & YSL
Kobenhavn K - camo bucket hat heaven
Carmen - amazing selection of everything, great accessories
I’m planning on going back to Copenhagen and when I do, I’ll be checking out these places too:
Red Cross (there were a few around)
Liafi Studio (men’s)
Bau Bau (men's)