The relationship between various characteristics of postharvest vegetables and their corresponding biological surface properties is strongly interconnected, leading to a broad spectrum of properties after irradiation. The primary objective of the present study was to investigate how different doses of Ultraviolet-C (UV-C) radiation affect the mechanical properties of semifinished potato tubers derived from distinct Polish varieties, namely, Innovator, Fineziya, and Victoria. A low UV-C dose ranging from 0 to 30 mJ/cm2 was administered. The Innovator variety, when subjected to irradiation, exhibited the highest levels of compression force, cutting force, and bending force. Additionally, the irradiated samples demonstrated improved resistance to compression force, bending force, and increased weight compared to the control samples. Conversely, the control samples exhibited higher resistance to cutting load than the irradiated ones in all varieties. The analysis of variance confirmed a significant difference in compression, cutting force, and tuber weight among the treatment samples in all varieties. Furthermore, stress-strain analyses were performed and showed an elastic behavior of the Victoria variety and a higher Young’s modulus for the Innovator variety.