Flood is one of the devastating natural disasters. By applying remote sensing technology, we determined the flood inundation areas, using the Synthetic Apertures Radar (SAR) sensor. Removing the speckles due to the phase fluctuations of the electromagnetic return radar signals by filtering 2 times image by using small kernel size to prevent losing information. The kernel size was 3×3. Removing the speckles by single filter and double filters, we applied and combined14 kind of filters (Low Pass filters, Gaussian Low Pass filters, Median filters, Sobel filters, Roberts, User-defined convolution filter, Lee filters, Enhanced Lee filters, Frost filters, Enhanced frost filters, Gamma filters, Kuan filters, Local sigma filters, and Bit error filters). Using a single filter the best filter is Gamma filter and for the double filter, Local Sigma filter combined with Low Pass filter, Enhanced Frost and Enhanced Lee. The Sobel filter, Kuan filter and Robert filter could not be applied for flood inundation analysis because these filters are unable to reduce the speckle and prevent information.