Given the high demand for water, the increase in evapotranspiration as a result of global warming of the planet threatens the sustainability of rice cultivation. This study aimed to estimate the foliar water stress index (Crop Water Stress Index-CWSI) from processing of thermal images obtained by remote sensors, as a tool for transiting from a plant scale (canopy) to a larger scale. The study was conducted at La Molina, Peru during the autumn-winter period (February-August, 2017) of cultivation of International Rice 43 variety under drip irrigation. Information regarding temperature of canopy was obtained using a FLIR thermal camera adjusted with information from thermocouples and correlated with volumetric soil moisture information measured with frequency domain reflectometry sensors. The CWSI was obtained from the foliar temperature adjusted to atmospheric conditions, such that dry temperature represents minimum transpiration (stomata closed) and wet temperature represents maximum transpiration (fully open stomata). In the reproductive and maturation phase of the crop, it was recorded that humid temperature was 15.2 ºC and 15.4 ºC and dry temperature was 33.7 ºC and 36 ºC, respectively. A significant Pearson correlation coefficient of −0.522 was obtained between CWSI and volumetric soil moisture at a significance level of 5% at 0.3 m of soil depth. It is therefore recommended that CWSI should be utilised during the monitoring of crop physiological variables. In addition, more optimal irrigation schedule and reduction in water consumption should be implemented.