We investigate the potential for optical quantum technologies of Pr3+:Y2O3 in the form of monodisperse spherical nanoparticles. We measured optical inhomogeneous lines of 27 GHz and optical homogeneous linewidths of 108 and 315 kHz in particles with 400- and 150-nm average diameters, respectively, for the D21(0)↔H43(0) transition at 1.4 K. Furthermore, ground-state and D21 excited-state hyperfine structures in Y2O3 are here determined by spectral hole burning and modeled by complete Hamiltonian calculations. Ground-state spin transitions have energies of 5.99 and 10.42 MHz, for which we demonstrate spin inhomogeneous linewidths of 42 and 45 kHz, respectively. Spin T2 up to 880μs was obtained for the ±3/2↔±5/2 transition at 10.42 MHz, a value which exceeds that of bulk Pr3+-doped crystals reported so far. These promising results confirm nanoscale Pr3+:Y2O3 is a very appealing candidate to integrate quantum devices. In particular, we discuss the possibility of using this material for realizing spin-photon interfaces emitting indistinguishable single photons.