Herein, the physical properties of Sr2MWO6 (M = Ca, Mg) double perovskite oxides are evaluated using an ab initio technique with full‐potential linearized augmented plane wave (FP‐LAPW) method. It is revealed that Sr2CaWO6 and Sr2MgWO6 are direct bandgap (Eg) compounds with Eg of 4.4 and 4.3 eV, respectively. The stability of Sr2MWO6 (M = Ca, Mg) compounds is in cubic lattices, which is ensured by calculating the tolerance factor (τ) and formation energy (ΔH). The optical features such as dielectric constants (ε1, ε2), optical conductivity σ(ω), refractive index n(ω), absorption coefficient α(ω), extinction coefficient k(ω), and reflectivity R(ω) are computed within the energy span of 0–10 eV. Finally, BoltzTrap code is utilized for the calculations of thermoelectric (TE) properties and the calculated values of figure of merit (ZT) for Sr2CaWO6 and Sr2MgWO6 are 0.7775 and 0.7471, correspondingly. The analysis of optical and TE characteristics indicates that the Sr2MWO6 (M = Ca, Mg) compounds are suitable for ultraviolet photodetectors, solar cells, and TE applications.