Two quasi-experimental field studies (N = 419; 248) tested the effects of an outdoor environmental education program based in local Protected Natural Areas (PNAs) on 3rd-to-6th-grade students' proenvironmental attitudes and behaviors. Results show the program increases children's place attachment, proenvironmental attitudes, ethics and self-reported behavior, and their parents' proenvironmental attitudes: Young people's experience with PNAs enhances their attitudes and behaviors toward environmental sustainability. The research addresses the crucial role of local PNAs in promoting proenvironmental attitudes and behaviors, highlighting the strategic importance of intervention procedures and moderators for environmental education activities applied to specific social-physical contexts.