This paper presents a theoretical framework that integrates supply-side decisions by tourism operators and demand-side responses by visitors to changes in coral reef conditions and related trip attributes, capturing both degradation and restoration pathways. The integrated model is tailored to the characteristics of the Australian Great Barrier Reef, accounting for regional heterogeneity, operator diversity, and tourist preferences. A key contribution is the incorporation of bidirectional ecological change and dynamic feedback between supply-side decisions and demand-side behaviour, linked through a transformation function that maps ecological reef condition to perceived attractiveness. By combining agent-based random utility models for operators and visitors, the model enables scenario testing under alternative reef health trajectories. The approach provides actionable insights for policy design, demonstrating how changes in reef quality influence substitution effects in terms of changing visitation probabilities, operator adaptation, and the economic benefits of restoration investments. This theoretical model provides the basis for a decision-support tool for dynamic management strategies aimed at sustaining coral-reef tourism under environmental uncertainty.