This paper presents basic knowledge of river plumes (RPs) that are formed when fresh water from rivers is issued into seas and oceans. Due to density difference, very often, river water will detach from the bottom of river estuaries to flow above denser sea or ocean water to form RPs. Research has shown that RPs have essential contribution to the dispersal of suspended sediment and hydrocarbon substances far into seas and oceans. The deposition of those matters potentially forms hydrocarbon sources which may anticipate the existence of offshore oil reservoirs. Next, this paper reviews useful information on the Red River RP in the East Vietnam Sea. Finally, some results of numerical simulation of RPs in experiments using a 3D-turbulence model (i.e. the EFDC model - Environmental Fluid Dynamics Code) will be shown.