Irrigation systems face unforeseeable changes in climate, technologies, and societal preferences during their lifetime, potentially rendering them obsolete or inadequate. To remain functional, irrigation systems need to be adaptive to changes as the future unfolds. Past approaches to irrigation system design were largely informed by engineering or economic criteria. This is increasingly recognised as insufficient. We provide examples of contemporary irrigation systems in Australia to highlight the need for planning and design approaches that recognise the complex interactions between human and water systems and embrace unknowns. We review literature on hydro-social interactions and dynamic adaptive pathways to provide insights for the development of adaptive irrigation systems.