A support system for outdoor learning using exploratory observation was developed. The system uses radio frequency identification (RFID) tags and two-dimensional (2D) symbology tags to locate positions on a horticultural farm and its surrounding forests. Students were able to get a location-dependent description and an educational hint for exploration by using a device to detect the tags. A small personal computer with an RFID reader was used to detect the RFID tags and show their corresponding information. A mobile phone with a camera was used to read the 2D symbology tags and retrieve the information. An experiment using the system was conducted in a course for practical studies of nature observation. After an exploratory observation, an evaluation was conducted using a questionnaire. The evaluation showed that both the RFID and 2D symbology tags were regarded highly by the students, that the system was useful for outdoor learning, and that the 2D symbology tag system using a small and lightweight mobile phone was preferred. (Contains 12 figures and 2 tables.)