The study presents the results from a project in which a 3D multi-user virtual environment was used for informing students on issues related to the protection of the Mediterranean monk seal. The target group was 326, 10-12-years old students divided into three groups. The first one was taught using printed material, the second used a web-based application, and the third used the virtual environment. Data were collected by means of evaluation sheets and three questionnaires for recording students' views and attitudes. The third group of students had better learning outcomes compared to the first, but the results were inconclusive compared to the second. Then again, the MUVE had a notable impact on students' attitudes toward seals compared to the other tools. As for attitudes toward eco problems, the outcomes were better only compared to the first group. Moreover, fun and an increased motivation for learning were evident in the third group but co-existed with significant problems related to the use of the virtual environment. The findings point to the need for further examination of the use of multi-user virtual environments for raising the awareness of environmental issues.