In this paper, we study the determinants of the transport mode choice of the trips to and within protected areas among the Czech adult population and the potential to change from cars to more sustainable transport modes. To do so, we designed a series of choice experiments. We distinguish one-day trips by couples (without children), one-day trips by families with children, weekly visits by couples, and weekly visits by families with children. The scenarios consist of various combinations of monetary costs of trips, travel time, characteristics of the environment around the parking lot/public transport stop, and the parking fee. In addition, various socio-demographic characteristics of the respondents were collected. Parking fees effectively reduce car usage even for travelling within protected areas. In the case of both couples and families, an increase in parking fees by 50% would decrease the share of cars by 6 p.p., and other modes (public transport, walking and cycling) would gain about 2 p.p. each. The travel time is also important: the reduction of the time spent in public transport by 20% would lead to an increase in public transport share by 3 p.p. and a decrease in car share by about 2 p.p. The relative strength of travel time and financial costs differ from travels to the protected areas. For families with children, the parameters of public transport (travel time, price) have negligible effects on the stated modal split.