The preferred temperature of Tegula regina was determined in a horizontal thermal gradient with organisms acclimated to 16°C, 19°C, and 22°C using to acute method, with a preferred temperature of 19.7 ± 1.8°C for the day cycle and 18.8 ± 1.2°C for the night cycle. The final preferred temperature determined for marine snails was 19.2 ± 1.5°C. The displacement velocity decreased to an interval from 99.1 cm/h to 62.5 cm/h. During the third hour, when organisms detected the preferred temperature, the velocity diminished gradually from 25.8 cm/h to 7.5 cm/h. Critical temperature maxima (CTMax), which refers to the temperature at which at least 50% of the experimental group displays a loss of attachment, was measured at three acclimation temperatures (16°C, 19°C, and 22°C). At the acclimation temperature (16°C), 50% of the experimental group had an attachment loss at a CTMax of 29.3°C. At a warmer acclimation temperature (22°C), the observed CTMax was 31.2°C. Marine snail oxygen consumption rate increased significantly (P < 0.05, 31%) from 16°C to22°C.