Silicon Photomultipliers are single-photon sensors working in Geiger mode. They are used in a wide range of applications, from high-energy physics to space and medical imaging. In some applications, they can be exposed to a significant amount of radiation, in the order of 1012−1014 neq/cm2 in high-energy physics or in the order of 109−1012 neq/cm2 in space for 5 years LEO orbits. In this contribution, we present an analysis of the main effects of the protons irradiation on the functional performance of several FBK SiPM technologies, with doses compatible with space missions along LEO orbits. In particular, we irradiated the SiPMs at the Protontherapy Center in Trento with proton fluences between 7.4×106 neq/cm2 and 6.4×1011 neq/cm2. During the irradiation test, reverse current-voltage (I-V) measurements were performed on the devices after each fluence step, and key parameter as Dark Count Rate and Photon Detection Efficiency were estimated. An annealing test was conducted at room temperature on all the devices for one month, performing reverse I-V measurements once a day. Lastly, results are showed and conclusions are drawn