Globally, there is a growing societal need for multifunctional coastal climate adaptation of sandy shores in the coming decades. Sand nourishment strategies are increasingly regarded as promising nature-based approaches to adaptation. They may increase flood safety and mitigate coastal erosion while enhancing recreational and ecological functioning. However, their multifunctional potential has not yet been assessed under diverse climate impacts at decadal scales. This study analysed the effects of beach, shoreface and mega-nourishment strategies on the physical capacity of sandy shores to supply coastal multifunctionality, using a systems-based approach. Through a structured literature review, we identified eight indicators for recreational (2 indicators), ecological (3) and flood safety (3) functions. We integrated these indicators into a process-based sand distribution model for dissipative coastal profiles. We simulated indicator states as the coastal profile responded to the nourishment strategies under five sea-level rise scenarios and three erosion rates. Next, we calculated the extent to which the physical capacity for coastal functions and multifunctionality were supplied over six decades. Our results indicate that all three nourishment strategies can highly supply the capacity for coastal multifunctionality, although the drivers of this potential differed per strategy. These findings imply that sand nourishment strategies are viable approaches for multifunctional coastal climate adaptation in the coming decades. However, they require prioritising specific coastal features and functions. Although sand nourishment strategies remain high-impact interventions, they also allow for intentionally creating coastal landscapes. These landscapes may not only provide flood protection but also enhance the specific environmental and societal functions valued in dissipative sandy shores. Prioritising among these functions requires explicit political choices.

Increased climate impacts threaten coastal functions globally, highlighting the need for multifunctional coastal climate adaptation. Sand nourishment can adapt sandy coasts to sea level rise, mitigate erosion, increase flood safety, enhance ecological habitats and expand recreational space. Therefore, sand nourishment is increasingly regarded as a promising nature-based strategy for coastal climate adaptation. However, despite this growing recognition, the assessment of how sand nourishment design impacts multifunctional adaptation remains limited. In this perspective article, we argue for three key lessons for researchers to optimise assessing multifunctional coastal climate adaptation by sand nourishment. We conducted stakeholder workshops to scope and inform our perspective, performed semi-structured literature reviews to concretise and validate this for international applications, built a qualitative model to visualise our interdisciplinary overview of how nourishments impact coastal multifunctionality, reflected on this in expert workshops, and identified implications for researchers. In this manner, we assessed the effects of nourishment design on coastal morphology, ecology, socio-economics and ecosystem services in realising the key policy goals of flood safety, nature and recreation. We found that sand nourishment design can result in conflicts between policy goals, generate ambiguous outcomes and lead to system-wide feedback effects. As such, we identified three key lessons: (1) conflicts between policy goals require informing political decision-making on prioritisation between coastal functions, (2) concreteness is needed on otherwise ambiguous functions, and (3) ongoing, multidisciplinary system-wide monitoring is essential. We thus call for a holistic approach to sand nourishment design and encourage researchers from diverse expertise and localities to expand on and adapt our findings to optimise informing sand nourishment design for delivering multifunctional coastal climate adaptation worldwide.