Most established laboratories that perform physical modelling have particular methods for hydraulic model studies. Physical modelling procedures in different laboratories vary in e.g. wave generation techniques; typical storm sequences; wave calibration techniques; scaling of short duration (impulsive) loadings; scaling of permeable materials; monitoring of damage and quantifying small armour movements; overtopping analysis; analysis and verification procedures; factors of safety etc. The potential differences in modelling results are difficult to judge, but may be significant in some cases. Reliable comparison of model test results will only be possible if the test set-up, measurement techniques and modelling approach are verifiably (i.e. geometrically, dynamically and kinematically) similar. This is often not the case, so comparisons between model results from different laboratories and data transfer between laboratories are complicated. This paper presents new guidelines (available for download at http://www.hydralab.eu/) to form a basis for a more unified physical modelling approach, which simplifies data transfer and the interpretation of modelling results gathered by varying laboratories and modelling approaches. To achieve this more unified modelling approach, guidelines for good laboratory practice in physical (experimental) model testing of coastal structures exposed to wave action have been developed.