Copenhagen's classic gay cruising spot is H.C. Ørsteds Park (Ørstedsparken), a central park beside Nørreport. Activity here is long-standing and generally tolerated, centred on the paths and greenery around the lake after dark. Amager Fælled, the open commons south of the centre, is a decades-old summer daytime cruising area near its car parks.
Both are public spaces, so use discretion and normal caution. Denmark is very LGBTQ+-friendly, but ordinary public-decency rules still apply.