The “Umwelt Digital 4.0” (environment digitized 4.0) research project represents an innovative approach to environmental education through mobile augmented reality (MAR) technology. This paper aims to present the conception and implementation of the AR mobile application that we designed for a nature discovery trail, which improves traditional environmental education through interactive digital experiences. The application utilizes smartphone sensors for environmental recognition and precise virtual object placement, enabling features such as 3D animal visualizations, historical reconstructions, and interactive learning stations. Through collaboration with NAZKA nature center, we developed and evaluated the application with 25 participants (average age 14.5 years). Results showed positive user engagement with most interactive stations rated 4 out of 5, while identifying areas for improvement in control schemes and age-appropriate content. The study reveals that AR technology can effectively supplement natural environment exploration while maintaining user engagement with physical surroundings. This work contributes to understanding how AR can be practically implemented in outdoor educational settings and provides insights for future developments in environmental education technology with a focus on MAR.