For hydrodynamic model testing different types of model waves are applied, where the most common ones are regular (monochromatic) and irregular (multichromatic) waves. In addition to these wave types the application of focusing wave groups, which are also often denoted as wave packages or transient wave packets, can give insight into aspects that cannot be assessed by the conventional model waves. This paper describes the different applications of focusing wave groups for hydrodynamic model testing. The paper starts with the historical background, followed by a theoretical description and the generation procedure. The main part of the paper is dedicated to the practical application of focusing wave groups in the basin. Items that will be described are a) the derivation of transfer functions for floating structures and for anti-roll tanks b) the determination of hydraulic and electrical transfer function of wave makers c) the verification of position and calibration of wave probes in the basin d) the generation of extreme wave events e) the assessment of reflection coefficient of beaches f) the investigation of non-linear aspects of transfer functions.