The QNeST Plus project "Quality Network for Sustainable Tourism" belongs to the European Programs INTERREG Adriatic-Ionian, in which partners, specializing in tourism, cultural heritage, Mediterranean diet and utilization of digital technologies, participate from countries: Greece, Italy, Slovenia, Croatia and Montenegro. An informative and co-creative online platform for the promotion of tourist routes was designed and developed, using special digital tools that facilitate accessibility and increase visibility. Businesses can participate in an international multilateral network of partner organizations, where they will be certified with the "Quality Brand" in terms of sustainable development and the promotion of sustainable tourism at local and transnational level. The Quality Brand concerns the traditional tangible and intangible cultural heritage in combination with the Mediterranean diet, as well as sustainable environment and social well being.