The combination of doped BaCeO3 and BaZrO3, modified by doping with Sr, Y, and Zn, was studied as a series of Ba1-xSrxCe0.7Zr0.1Y0.15Zn0.05O3−δ (BSCZYZn), with changing compositions of x = 0.1, 0.3, and 0.5. The X-ray diffraction analysis revealed a rightward shift in peaks, attributed to changes in the unit cell volume. For all compositions, the cell parameters and density decreased as the Sr content increased. Rietveld refinement confirmed that all compositions crystallize in cubic symmetry within the Pm-3 m space group. Scanning electron microscopy indicated that the materials have dense and well-connected surfaces. Thermogravimetric analysis of dried samples in air demonstrated significant thermal stability, promising proton uptake at higher temperatures. The minimal weight loss was observed for BSCZYZn10, and it was approximately 0.74% at 1000 °C. The largest average particle diameter measured in all components was around 117 µm. Among all compositions, BSCZYZn10 exhibited the highest ionic conductivity in wet 5% H2, achieving 3.03 × 10⁻³ Scm⁻¹ at 700 °C with the lowest activation energy of 0.381 eV.