Tourism is among the fastest-growing global sectors, contributing significantly to the gross domestic product (GDP) and employment. However, current rising demand, especially among coastal and marine destinations, has intensified pressure on ecosystems and natural resources. This chapter explores blue tourism and evaluates how green investment mechanisms can support the transition toward more sustainable tourism practices. Emphasis is placed on financial instruments, international policy frameworks, and certification mechanisms, such as the Blue Flag, which aim to balance environmental protection with economic opportunity. This chapter reviews global initiatives led by governments, international bodies, and private actors that seek to reduce pollution, manage overconsumption, and promote ecosystem resilience. Through in-depth case analyses and comparative policy insights, this chapter highlights the role of multilevel governance in enabling a more sustainable tourism model. Ultimately, this chapter provides a roadmap for integrating ecological responsibility into tourism planning, offering practical strategies for enhancing both the resilience and inclusivity of blue economy development.