The designation of protected areas (PAs) entails environmental, social, and economic effects to local stakeholders through access restriction to natural resources. We used a mixed methods research framework that combines time series analysis and stakeholder surveys to elicit objective and subjective effects of legal and managerial designation of Sierra Cabrera-Bedar Natura 2000 site on local sustainability in south-eastern Spain. Firstly, 47 environmental, social, and economic variables for which official time series data were available were assessed using a multiple-paired-Before-After-Control-Impact research design, where “Impacts” were: (1) legal designation of Sierra Cabrera-Bedar as a Site of Community Importance (SCI); and (2) management implementation of the site as an Special Area of Conservation (SAC). The two municipalities having most of their territories in Sierra Cabrera-Bedar SCI/SAC were selected as ‘Cases’, whereas two similar municipalities outside the PA were chosen as ‘Controls’. Additionally, 13 local organisations pertaining to 11 socioeconomic guilds from case municipalities were surveyed on their perceived effects of the designation Sierra Cabrera-Bedar as an SAC on 28 social and economic variables. The effects of legal and managerial protection of the site on local sustainability were unclear although greater SAC sustainability is suggested, even though limited time series availability for the SAC period increases uncertainty. Local organisations perceived mostly limited and negative socioeconomic effects from SAC designation. Disagreement between statistical and perceptual results suggests use of time series analyses for accurate assessment of socioeconomic effects of PAs in Spain.