This volume contains the proceedings of the 4th International Conference on Estuarine and Coastal Modelling held in San Diego, California, October 26-28, 1995. The conference included oral and poster sessions, describing recent model developments, applications, and interpretation and visualization of results. Special sessions were held on 2 and 3-D finite difference and finite element flow, baroclinc flow, forecasting and hindcasting, water quality, and sediment transport modelling. The poster sessions featured the presentation of a wide variety of evolving integrated systems for model application and visualization. Each paper in the publication was presented at the conference and underwent independent peer reviews prior to acceptance. The authors represent a well balanced mix of professionals from government, private industry and academic institutions of the U.S. and international countries.