Sea target detection in the HSP-FLSAR images has not been addressed so far in the literature. In this paper we carry out a comparative evaluation of existing SAR target detection algorithms in the case of monostatic HSP-FLSAR range Doppler images assuming a platform diving trajectory. To do so, various CFAR methods, including CA-CFAR, SOCA-CFAR, GOCA-CFAR, OS-CFAR, VIE-CFAR, and G0 distribution CFAR algorithms, are used to detect a set of point scatterers in simulated images. The performance of methods is compared based on receiver operating characteristic curves. Simulation results show that OS-CFAR has the best probability of detection for a fixed probability of false alarm. This paper can be a starting point to find better target detection methods in HSP-FLSAR images.