Global trends have enabled tourism to shift to sustainability. The tourism offer is largely dependent on natural resources. Therefore, their preservation is the main task of everyone involved in tourism. Eco certificates and green business are tools to protect the environment. They encourage environmentally responsible behavior through their criteria and green activities. Hotels accept eco certificates in their business in order to increase competitiveness in the tourist market. Although eco-certificates represent a positive change on the market, rapid expansion and lack of control created a problem where the credibility of eco-certificates cannot be recognized, i.e. whether the holder of the certificate complies with all measures and norms. ISO 14000 is the first step towards common standardization, according to which all eco-certificates will be guided. Hotels that have a certificate only because of profitability will lose their credibility as environmentally conscious and their place in the already competitive tourist market, because that same certificate will not represent a guarantee that they take care of environmental protection. In the empirical research, an example of the Dalmatia Green eco certificate of the association Sunce was studied. Similar criteria have been observed as the international standardization ISO 14000. However, in the research where the survey was sent to users of the Dalmatia Green certificate, a change in the attitude of the respondents was observed. They believe that the certificate offers them a certain benefit, but with or without the certificate, they did not notice a change in their business and continued to implement ecological standards and sustainable business.