Sustainable tourism in its purest sense is an industry which attempts to make a low impact on the environment and local culture, while helping to generate income, employment, and the conservation of local ecosystems.

It is responsible tourism that is both ecologically and culturally sensitive. Thus, Sustainable tourism activities have minimal impact on the environment and culture of the host community. According to the World Tourism Organization, sustainable tourism is tourism that leads to the management of all resources in such a way that economic, social and aesthetic needs can be fulfilled while maintaining cultural integrity, essential ecological processes, biological diversity and life support systems.

Taking a leaf from the definition of sustainability itself, sustainable tourism is also defined as a process which meets the needs of the present tourists and host communities whilst protecting and enhancing needs in the future. Sustainability principles refer to the environmental, economic, and socio-cultural aspects of tourism development, and a suitable balance must be established between these three dimensions to guarantee its long-term sustainability. Thus, sustainable tourism should make optimal use of environmental resources that constitute a key element in tourism development, maintaining essential ecological processes and helping to conserve natural heritage and biodiversity.

It should respect the socio-cultural authenticity of host communities, conserve their built and living cultural heritage and traditional values, and contribute to inter-cultural understanding and tolerance. It is also to ensure viable, long-term economic operations, providing socio-economic benefits to all stakeholders that are fairly distributed, including stable employment and income-earning opportunities and social services to host communities, and contributing to poverty alleviation. Sustainable Tourism refers to a level of tourism activity that can be maintained over the long term because it results in a net benefit for the social, economic, natural and cultural environments of the area in which it takes place.

The United Nations World Tourism Organization defines sustainable tourism as tourism that meets the needs of present tourists and host regions while protecting and enhancing opportunity for the future. Rather than being a type of product, it is an ethos that underpins all tourism activities. As such, it is integral to all aspects of tourism development and management rather than being an add-on component The objective of sustainable tourism is to retain the economic and social advantages of tourism development while reducing or mitigating any undesirable impacts on the natural, historic, cultural or social environment. This is achieved by balancing the needs of tourists with those of the destination.

John Beech and Simon Chadwick defined sustainable tourism as tourism that is economically, socio-culturally and environmentally sustainable. With sustainable tourism, socio-cultural and environmental impacts are neither permanent nor irreversible. Sustainable tourism has minimal impact on the environment and culture of the host community.