Infrared imaging provides a new way to detect internal waves under conditions where techniques that rely on backscatter from the sea surface may not be effective and it provides a new means to investigate the spatial variability associated with internal waves. This is illustrated with imagery collected in a bay under light winds using an airborne infrared camera. The internal waves appear as groups of dark and bright bands, corresponding to surface temperature fluctuations of about 0.05¿C. A signal of this size is shown to be plausible based on straining of the water's surface thermal boundary layer ('cool skin') by internal waves having a strain rate of the order of 10-2 s-1. In addition, fine-scale temperature structure was detected that we speculate may indicate instabilities induced by the internal waves.