We report the successful incorporation of ${\text{Er}}^{3+}$ ions into ${\text{SnO}}_2$ nanocrystals via a solvothermal method, with a resulting ${\text{Er}}^{3+}$ concentration of the order of ${10}^{19}{\text{cm}}^{-3}$ . Upon excitation above the ${\text{SnO}}_2$ bandgap at 300 nm, intense and well-resolved ${\text{Er}}^{3+}$ -related photoluminescence (PL) at $1.55\mu \text{m}$ was observed at room temperature. The results of PL excitation and ultraviolet/visible diffuse reflectance spectra indicate that the excitation is a carrier-mediated process with an energy transfer from the ${\text{SnO}}_2$ host to ${\text{Er}}^{3+}$ . For the above-gap excitation, only a single type of ${\text{Er}}^{3+}$ luminescence center located at a centrosymmetric site was identified. The near-infrared luminescence dynamics and the weak PL thermal quenching of ${\text{Er}}^{3+}$ were also revealed.