Very large subaqueous sand dunes were discovered on the upper continental slope of the Northeastern South China Sea. The spatial distribution and scales of these large sand dunes were mapped by two multibeam echo sounding (MBES) surveys, one in 2012 and the other in 2013. These two surveys represented two pilot cruises as part of a multiyear, US-Taiwan collaborative field study designed to characterize these sand dunes, the associated physical processes and the associated acoustic scattering physics. The main experiment will be carried out in 2014. The combination of MBES, coring and acoustic transmission data obtained from the two pilot cruises have provided vital initial knowledge of (1) the spatial and temporal scales of the sand dunes from objective analysis, (2) the geoacoustic properties of the dunes based on forward modeling to matching the measured levels, and (3) the anisotropy and translational variability of the transmission loss based on a signal energy analysis of the repeated 1–2 kHz and 4–6 kHz FM signals transmitted by a calibrated sound source towed along two circular tracks, each surrounding a receiver. The results from the pilot cruises are presented and discussed. [The research is sponsored by the US ONR and the Taiwan NSC.]