To meet growing demands for the separation and recycling of rare-earth elements, photo-assisted reduction followed by precipitation is increasingly recognized as a viable non-contact approach. However, only limited light sources are currently available for these processes, because most research has focused on excitation of redox active charge-transfer bands of lanthanoid ions in the VUV and/or UV region. In this study, we carry out the reduction of Eu3+ to Eu2+ with hydrated electrons generated in water by near-infrared femtosecond laser pulses under an air atmosphere. The reduction yields are not linearly dependent on either the laser power or the concentration of 2-propanol acting as a hydroxyl radical scavenger. Addition of sulfate ions precipitates Eu2+ as an insoluble EuSO4 after a certain indication time. The absorption/extinction spectroscopy and transmittance measurements reveal the reduction of Eu3+ and growth of sulfates during the induction time. The success of precipitation by a valence change in water under an air atmosphere opens an avenue for the practical use of near-infrared light for the treatment of lanthanoid elements.