Exposure to a thermally unstable environment causes work productivity loss, fatigue, stress, and respiratory complications. The current study investigated occupational thermal comfort in urban subway stations. The study was carried out in Chennai from March–June 2019. A monitoring campaign was conducted in seven urban subway stations using DeltaOhm HD32.3. The thermal parameters, temperature, relative humidity, and air velocity surpassed the regulatory standards given by ASHRAE-55 and ISO7730; the highest mean values approached 35 ºC, 80%, and < 0.1 m/s. Substantial low mean wet bulb temperature (< 26 ºC) shows that low room air temperature could be attained with evaporative cooling of air. Further, no significant impact of radiations and airflow was observed on comfort conditions. Thermal stress indicators, globe, mean radiant, and operative temperature values were similar to the dry bulb temperature. Furthermore, the estimation of comfort indices indicated subway occupational dissatisfaction of 36–99%. The Pearson’s correlation analysis illustrated that station characteristics significantly influence comfort conditions.