Recently, the application of the magnetic field during the solidification process of alloys has become of great interest, owing to its ability to enhance microstructures. Hence, the present work aims to study the impact of a rotating magnetic field on the microstructure, thermal, and creep properties of the Sn–2.0Ag–0.5Cu (SAC205) alloy during solidification. Results demonstrated that applying a rotary magnetic field homogenized the distribution of intermetallic compounds and improved the microstructure. Additionally, the magnetic field diminished undercooling from 22.5 oC to 11.4 oC, indicating that the magnetic field is very useful in enhancing the microstructure and the alloy’s reliability. The pasty range values for SAC205 and SAC205-B were 7.2 oC and 8.6 oC lower than 11.0 oC for lead-tin, leading to a reduction of the alloy porosity. The SAC205-B alloy exhibited the longest creep rupture time of 158.5% compared to the SAC205. The n values of SAC205-B were higher than those of SAC205. Consequently, the SAC205-B alloy displayed the highest creep resistance and lowest creep rate (28.53%) compared to the SAC205. The Q values were 51.2 and 67.5 kJ/mol for SAC205 and SAC205-B, respectively, controlled by pipe diffusion. This research will provide practical advice for the manufacture of the solder alloy.