Big Volcano Ecotourism Resource Centre: Comprehensive directory with worldwide links about ecotourism practice, ecologically sustainable development and general tourism and travel best practice management.
Earthfoot's Ecotour Posterboard: Provides worldwide links to local guides for personalised eco-tour experiences.
Eco Tour: Directory of ecotour operators with search by country or keyword.
Ecoturismolatino: Guide to protected areas in Latin America, with suggested itineraries and contact information. [English and Spanish]
Planeta.com: Virtual library archiving articles about ecotourism and conservation. Includes contacts and bibliographies.
Responsibletravel.com: Lists eco-friendly holidays with search by country and activity, and links to individual operators.