The stability of rock slopes under wave attack is addressed in this paper. Physical model tests have been conducted and analysed to obtain information on how to apply design formulae for conditions including situations in which wave breaking occurs on shallow foreshores. The analysis is based on tests on structures with a 1:100 foreshore and a 1:30 foreshore. It has been found that especially for applications with shallow foreshores the formulae by Van der Meer (1988) can better be applied a) by using the spectral wave period T _m-1,0 instead of the mean wave period T_m from time-domain analysis, b) by re-calibrating the coefficients, and c) by adapting the confidence levels. In addition, an alternative formula has been developed that, although it is simple, leads to the same accuracy for the more than 200 test conditions studied here.