Best cycling in Hong Kong that tourists never discover. Rent bikes at Sha Tin MTR station (about HK$50/day) and cycle along Shing Mun River. Completely flat, well-maintained, goes through different neighborhoods and parks.

8km one way from Sha Tin to Tsuen Wan. Takes about 45 minutes at a relaxed pace. Lots of spots to stop for local food and the river views are surprisingly nice. Way better than trying to cycle on Hong Kong Island's hills.