This research examines how nature-based tourism operators within coastal ecosystems employ Knowledge Management (KM) in the pursuit of nature-based solutions (NbS) to sustainability challenges. NbS are achieved at the intersection of the physical environment, climate, ecosystems, biodiversity, and socio-economic and socio-cultural systems. NbS integrate diverse types and systems of knowledge to be acceptable to a range of stakeholders. To explore these knowledge types and systems, a qualitative, multiple-case-study approach is used, with interview data collected across different organizational levels of nine discreet nature-based tourism operation cases from Australia, Malaysia, Thailand, and Vietnam. Our findings highlight how these tourism operators have developed practices to manage diverse knowledge systems in the pursuit of sustainability outcomes and provide critical insights into how more sophisticated approaches to such sustainability knowledge management (SKM) may lead to more optimal NbS and sustainable tourism outcomes for vulnerable marine ecosystems.