What is the difference between Vadsø, Vadsøya and Varanger?

Short answer

Vadsø is the town and the municipality. Vadsøya is the island just south of the town, with the Airship Mast, walking paths and a bird reserve. Varanger is the region around the Varangerfjord and the Varanger Peninsula — and Vadsø Municipality also includes the villages of Ekkerøy, Skallelv and Vestre Jakobselv. See Vadsøya on the culture trail.