To study the relationship between the short-wavelength infrared reflectance and the moisture content in the beach, we conducted a rigorous analysis using regression models under different parameter settings defined by band selection, average grain size, and sand mineralogy. The spectral reflectance data were collected by a hand-held spectrometer with 3-6 nm spectral resolution. The grain sizes measured from 0.15 to 0.92 mm, with an average of 0.75 mm. The mineral components were Quartz-Alkali Feldspar-Plagioclase and Calcite-Quartz-Alkali Feldspar-Plagioclase. We found the best spectral bands were located at 1400, 1900, and 2200 nm. The regression model on these selected bands yielded an R-squared over 0.74 and RMSE lower than 0.05. We expect this study to contribute toward understanding the spectral response of beach sand with regard to its moisture content more clearly as we also consider its mineral composition and grain size.