Effective protected area (PA) conservation relies heavily on positive social perception, attitude and values, especially by the stakeholders most affected by PA regulations. Random samples of residents around (n = 401) and quota samples of visitors to (n = 542) two emblematic, environmentally similar National Parks (NPs) in Spain: Ordesa y Monte Perdido NP (Ordesa NP) and Sierra de Guadarrama NP (Guadarrama NP) were surveyed on their attitudes, perceptions and values using structured questionnaires. The results show similarities and differences between stakeholder groups and NPs. Most differences can be explained by the different geographic, historical and socioeconomic contexts. Residents near Guadarrama NP visited it less frequently, whereas non-residents visited the NP more frequently than Ordesa NP. Residents' and visitors' perception on the conservation state was better for Ordesa NP than for Guadarrama NP. The main perceived threats by both groups were wildfires, massive visitation and insufficient environmental awareness. Local participation in management was deemed improvable in both NPs. Stated importance on both NPs was similarly high for both stakeholder groups. Half of residents and over two-thirds of visitors to both NPs were willing to pay an entrance fee. A daily fee of 3 € per person would be acceptable to most. Willingness to pay (WTP) was negatively correlated with 'frequency of visits' in Guadarrama NP. WTP increased substantially with measures that ensure equity, transparency and accountability. These results present PA managers with updated key stakeholders' attitudes and perceptions, and provide a feasible alternative to regulate massive visitation and enhance financial sustainability of Spanish NPs.