The geothermal energy does not pollute the environment and atmosphere during production and consumption. Akarcay basin (Afyonkarahisar) has significant geothermal potential in Turkey. Geothermal waters in the basin are used for tourism, residential heating, greenhouse, and balneological applications. Hydrothermal alteration zones are essential indicators for the exploration of geothermal fields. In the feasibility studies of geothermal exploratory studies, outcrops of alteration contribute significantly to the exploration studies in investigation of target areas. The use of remote-sensing techniques in the detection of hydrothermal alteration minerals spread over large areas enables large areas to be evaluated holistically, saving both time and economically and achieving effective results. In this study, the Crosta and Spectral Angle Mapping (SAM) techniques were applied to determine the hydrothermal alteration zones by using ASTER satellite data. In this context, samples from hydrothermal alteration zones were collected from the study area. The mineralogical compositions of studied samples were determined by using X-ray diffraction (XRD) method. Alteration zones were also distinguished in similar locations in mapping techniques and XRD method. The results were combined, and the final alteration zones were formed. The alteration zones masked with volcanic and metamorphic rocks in order to be a geothermal indicator of hydrothermal alterations. The existing alteration zones are almost on the existing geothermal fields. As a result of the study, alteration zones were proposed different from the existing alteration zones. It is expected that these zones will be a reference in future geothermal explorations.