Environmental and disaster consciousness of teachers are of great importance for disasters education. The teaching of some natural disasters of climate in the Environmental Problems course at an education faculty in Turkey was carried out with the Problem Based Learning (PBL) approach supported with Instructional Geocaching Game (IGG). Geocaching is an outdoor location based-digital game in which players hide a box and then share its coordinates online. Other players can find it with GPS. IGG is an educational game played with small student groups designed by teachers. This study aims to demonstrate how the IGG activities conducted outside of the classroom with the PBL approach are applied and IGG's outcomes. The instrumental case study design was utilized with a group of 19 geography prospective teachers whom were selected by convenience sampling method. The students' views on the IGG were determined by the open-ended questionnaire and their behaviours were determined by out-of-classroom observation forms. Student performances were evaluated through the IGG portfolio. Document analysis for survey and portfolio data; descriptive analysis for observations were done. The findings revealed that students' problem-solving skills increased and they learned to use GPS technology; IGG contributed to the development of environmental awareness and disaster awareness of them by increasing motivation. In addition, some strategies for the practice of the game emerged. IGG facilitated students' PBL process and it was evaluated as a geography game by students. According to the results, the PBL-IGG approach is applicable in Geography and Environmental Problems courses.