Multi-purpose floating platforms are emerging as a promising concept in ocean engineering applications, thanks to their capability of ensuring system integration, cost reduction and modularization. However, their increasing complexity requires the development of numerical tools, which need to be validated experimentally through adequate physical models. New challenges hence arise, since the subsystems integrated in the structure generally follow different scaling laws and may need relatively large physical models to achieve a reliable similitude between the full-scale structure and its physical model counterpart. The latter issue can be critical, because indoor tests in wave tanks and basins constrain the scale factors to the size of the available facilities. Open-sea experiments, albeit challenging because of the uncontrolled environmental conditions, could be a valid complement to the traditional indoor tests. This article proposes a review of the multi-physics scaling strategies for the subsystems usually embedded in multi-purpose floating platforms, i.e. floating support, mooring system, wind turbine, wave energy converter and aquaculture facilities, by providing a critical analysis on the relevance of the scaling factor and of the scaling strategy. The paper may also serve as a guide for practical applications involving one or several of the considered subsystems.