Tourism in protected areas can create considerable income for adjacent communities. Based on face-to-face visitor surveys, the present study measures the structure, size and economic impact of tourist expenditure in the six German national parks Niedersächsisches Wattenmeer, Bayerischer Wald, Eifel, Müritz, Hainich and Kellerwald-Edersee. We find that mean daily expenditure per person is considerably below the national averages for tourists in Germany: day-trippers spend between EUR 7 and 13 per day (national average: EUR 28), whereas overnight visitors spend between EUR 37 and 57 (national average: EUR 120). The proportion of visitors with high national park affinity varies between a maximum of almost 46% in Bayerischer Wald and a minimum of nearly 11% in Niedersächsisches Wattenmeer. Between 49% and 51% of tourist expenditure is captured as direct and indirect income. The total impact of tourism ranges between EUR 525 million in Niedersächsisches Wattenmeer and EUR 1.9 million in Kellerwald-Edersee, reflecting the national parks’ distinct trajectories as tourist destinations. In order to increase the economic benefits accruing from national parks regional policy could aim at a qualitative upgrading of tourist services, increased marketing of the unique national park label and the promotion of a diverse regional supply base.