This paper presents a comprehensive review of boundary element methods for hydrodynamic modelling of wave energy systems. To design and optimise a wave energy converter (WEC), it is estimated that several million hours of WEC operation must be simulated. Linear boundary element methods are sufficiently fast to provide this volume of simulation and high speed of execution is one of the reasons why linear boundary element methods continue to underpin many, if not most, applied wave energy development efforts; however, the fidelity of the physics included is inadequate for some of the required design calculations. Judicious use of non-linear boundary element methods provides a route to increase the fidelity of the modeling while maintaining speed and other advantages over more computationally demanding alternatives such as Reynolds averaged Navier–Stokes (RANS) or smooth particle hydrodynamics (SPH). The paper presents some background to each aspect of the boundary methods reviewed, building up a relatively complete theoretical framework. Both linear and nonlinear methods are covered, and consideration is given to the computational complexity of the methods reviewed. The paper aims to provide a review that is useful in selection of the most appropriate techniques for the next generation of WEC design tools.