|Nature protection areas are often significant and attractive recreation areas and tourist destinations. In Finland, Metsähallitus manages most of state owned protected areas. Thus, Metsähallitus also has a significant responsibility for tourism development in these areas. As a part of a larger Metsähallitus project to promote sustainable nature tourism in protected areas, the organization has developed measures for estimating the environmental impacts of nature tourism in protected areas. The measures are derived from Metsähallitus’ nine principles of for sustainable nature tourism, including the aspects of ecological, socio-cultural, and economic sustainability. The indicators have been tested in six pilot areas across Finland. This article describes the process of developing indicators, and the ways in which the indicators are being and will be used through incorporating them into the overall planning process. Sustainability is approached by setting standards, i.e. defining the limits of acceptable change, for each indicator. While some of the indicators are ready to be used, further development and testing is still required.