According to UN Tourism, sustainable tourism is tourism that takes into account its current and future economic, social, and environmental impacts, while addressing the needs of visitors, the tourism industry, and local communities. Its goal is to ensure that the benefits of tourism are sustained for future generations.

Ecotourism is a form of nature-based tourism, such as visits to forests, islands, rivers, or marine parks, with an emphasis on environmental conservation and benefits for local communities.

Responsible tourism, on the other hand, refers to the ethical practices of all stakeholders involved in tourism. This includes maintaining cleanliness, respecting local culture, complying with regulations, and supporting local businesses.

In short, sustainable tourism is the overarching goal, ecotourism is one form of nature-based tourism, while responsible tourism refers to the practices that support sustainable tourism.