This article concerns the self-similarity of sea surface temperature (SST) patterns. This study is based upon analysis of the NOAA AVHRR infrared images of the northern Japan Sea from April 1990. Calculations of isotherms lengths provide experimental evidence of the fractal properties of the SST patterns as tracers of the sea mesoscale turbulence. The isotherms fractal dimension is found to be 1.27 ± 0.07 for space scales from at least 4 km to approximately 120 km. This value is in complete agreement with that of drifting buoys trajectories in the Kuroshio extension. Estimation of sequences of the mass exponents shows that the sea surface temperature patterns exhibit monofractal rather than multifractal behaviour. Consideration of the series of the NOAA AVHRR infrared images reveals self-similar turbulent structures—the chains of vortices consisting of vortex pairs and anticyclonic eddies. Such hierarchies of these vortices, whose horizontal size grows from several kilometers to approximately 100 km, exist for at least 20 days. Their evolution and possible mechanism of formation are discussed.