Book excerpt: Free-surface flow (or wave) interaction with vegetation is a complex subject. In order to understand the underlying physical processes either physical experiments or numerical simulations, or ideally in complement, can be employed. Both approaches face lots of challenges. For example in experiments, the research question is how to scale-down appropriately the large-scale physics and how to interpret the experimental data. In numerical simulations, how to approximate numerically the complex wave-multiple rigid or flexible structures (vegetal stems) including the resolution of turbulence at all spatial and temporal scales. This book reviews the state of the art of the research in the area of wave-vegetation interaction for coastal applications using numerical and experimental approaches. The reference text will be useful to students, early-career researchers, teachers and practicing engineers in the field of ocean engineering, civil engineering and climate change.