Basaltic terrain has potential with regard to the production of geothermal energy and the feasibility of underground storage of nuclear waste disposal sites, where heat plays a vital role in governing the physicomechanical properties. Accordingly, this study focuses on the evaluation of the effects of heating on the physical properties and Brazilian tensile strength of basaltic rock collected from the Rajahmundry Traps, Andhra Pradesh. The prepared core specimens from the collected blocks were subjected to heat treatment at room temperature, 100 °C, 200 °C, 300 °C, 400 °C, 500 °C, 600 °C, and 800 °C. Subsequently, physical properties like porosity, mass, change in colour, ultrasonic P-wave and S-wave velocities, and Brazilian tensile strength were measured. It is found that porosity increased by ~ 145% (1.40–3.45), and ultrasonic P-wave and S-wave velocities decreased by ~ 38% (5551.67–3445.67 m/s) and ~ 33% (3433.67–2658.67 m/s), respectively, at 800 °C with reference to untreated samples. The Brazilian tensile strength also decreased by ~ 44% from 16.45 MPa to 9.26 MPa due to heat treatment with reference to untreated samples. These outcomes may be attributed to an extension of existing microcracks or the formation, propagation, and coalescence of thermally induced microcracks. The outcomes of this investigation will be effective in various underground geoengineering applications where heat plays an important role.