Limestone and sandstone are widely used in engineering, yet their behavior remains poorly constrained under combined thermal exposure and water saturation. We experimentally evaluate how temperature (22–750 °C) and saturation alter key physical and mechanical properties of these rocks using a consistent test matrix on 136 cores. Mass, density, and ul-trasonic pulse velocity (UPV) were measured before and after heating; the strength was quantified by uniaxial com-pressive strength (UCS) and Brazilian tensile strength (BTS). Both rocks retained capacity up to ~450 °C, with limestone stronger than sandstone. Above this threshold, the strength and UPV declined markedly, reflecting thermal cracking; limestone showed pronounced density loss at high temperature, consistent with mineral decomposition. Saturation reduced strength in both lithologies, with a larger drop in limestone, and changes in density and UPV tracked these trends. The conceptual advance is a side-by-side, cross-property comparison that links thermal and hydraulic states to coupled changes in mass, density, UPV, UCS, and BTS for two common sedimentary rocks. These results provide practical bounds for designing and assessing rock materials and rock-hosted infrastructure exposed to heat and moisture, from tunnels and foundations to fire and geothermal scenarios.