Various applications, like for instance algorithm design, mission planning, geo-referencing, change detection, Automatic Target Recognition (ATR) or SAR data analysis, rely on simulated synthetic aperture radar (SAR) images. However, there are different SAR simulation techniques with different advantages and disadvantages. Depending on the needs of a certain application, a suitable SAR simulation technique has to be used. This paper compares three SAR image simulation approaches, RaySAR, CohRaS (R), and SARViz, showing their similarities and differences. RaySAR and CohRaS (R) are two ray tracing based SAR image simulators. RaySAR is based on the open-source software POV-Ray, while CohRaS (R) is developed as SAR simulator from scratch. The third simulator, SARViz, is a real-time SAR simulator based on the rasterization approach. The geometrical features of the three simulators are compared and the differences and different applications are analyzed. (C) 2014 The Authors. Published by Elsevier B.V. on behalf of International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). This is an open access article under the CC BY-NC-ND license.