Zalesin [zaˈlɛɕin] is a settlement in the administrative district of Gmina Ustka, within Słupsk County, Pomeranian Voivodeship, in northern Poland. It lies approximately 9 kilometres (6 mi) south-west of Ustka, 22 km (14 mi) north-west of Słupsk, and 126 km (78 mi) west of the regional capital Gdańsk.

For the history of the region, see History of Pomerania.