The dye injection method and the oil film method together with electromagnetic velocimetry were applied to the flows around groins under submerged conditions. The flow is highly three-dimensional and unsteady through the formation of mciitulation zones and surface waves. The approaching flow to the forefront of groin leads to the downward current that alternate flow directions. In particular, the flow towards groin tip near bed is accompanied by strong rotational motion relevant to local scouring there. At the rear side of the groin, the primary recirculation zone is generated mainly by the overflow and shows complex structure due to the presence of secondary currents and the interaction with the flow outside of the groin For the groin interval larger than 20cm, the flow structure shows no significant change and the effect of groin on the velocity distribution extends away from groins The flow characteristics using the oil film method show high consistency with the velocity distribution by electromagnetic current meter.