An excellent market-driven way to successfully implement sustainable tourism in a destination is to find a segment of tourists or potential tourists interested in the unique natural beauty of the destination, willing to preserve it and who are also highly attractive in terms of high expenditures, long stays, high return rate, high recommendation rate etc. The first step in seeking these visitors is thorough investigation of sustainable market segments. So far, only a few studies have systematically searched for “eco-segments” or sustainable tourist groups and described them. This paper reviews the usefulness of such approaches, examines past studies investigating potential target segments and describes the group of summer tourists in Austria who care about maintaining the natural environment. The results suggest that this group of visitors has some highly attractive characteristics and is very large, thus offering a sound basis for additional sustainable niche segment creation.