This paper briefly reviews the theory behind wave measurement with HF radar. Data from a number of different deployments with different radars, at different frequencies, in different oceanographic conditions are used to demonstrate the wave mapping capability and to illustrate some of the problems that have arisen and solutions that have been identified. The examples show the spatial variability in coastal wave fields and hence demonstrate the value of HF radar measurements for wave-sensitive coastal engineering applications and for wave model validation and development.