We report on surface-plasmon propagation along coupled coplanar cavities periodically distributed in an otherwise unperturbed plasmonic crystal. We show that the dispersion of particular Bloch modes can exhibit multiple energy gaps that can be adjusted by choosing the cavity size. For resonant sizes, the composite crystals composed of juxtaposed cavities can support plasmon modes at frequencies within the gap of the unperturbed grating. In this case, we demonstrate that the surface-plasmon propagation relies on a hopping In this work, we demonstrate surface-plasmon polariton SPP hopping along a composite plasmonic crystal consist- ing of coupled coplanar cavities. We show that the spectral properties of the composite crystal are dramatically changed compared to those of the perfect crystal. In particular, we discuss the occurrence of multiple energy gaps in the disper- sion curve of the SPP mode for specific cavity sizes. For frequencies within the energy gap of the unperturbed mirror, we show that the propagation along the composite crystal relies on the SPP hopping. When this hopping mechanism occurs, we observe a clear localization of the electromag- netic field within the cavities, a feature that could be of key interest for controlling and enhancing SPP-matter interaction in the context of nonlinear active plasmonics and for quan- tum electrodynamics applications. 5 A typical structure considered in this work is shown in Fig. 1. It consists of microgratings of gold ridges with a period a deposited on a gold thin film lying on a glass sub- strate. Two adjacent microgratings are separated by a thin film area with a length a+ which forms a coplanar one- dimensional SPP cavity. 6 In reference to integrated optic de- vices, the composite plasmonic crystals obtained by juxta- posing the cavities will be called sampled Bragg mirrors SBMs 7 in the following. If N denotes the number of lines between adjacent cavities, the period of the SBM is given by d=Na+.