This research examined the effect of a course designed with different content on pre-service science teachers' self-efficacy beliefs and knowledge about organizing curriculum-based trips. A pretest post-test quasi experimental design was used in the research. One-hundred and thirty pre-service science teachers participated in the research. The research was carried out within the context of an elective course called "Informal Learning Environments in Science Education" and was conducted over 14 weeks in total for two hours per week. The research data were obtained by means of a questionnaire, self--efficacy scale for designing curriculum-based field trips (CFTSES) and semi-structured focus-group interviews. As a result of the research, it was found that the course content which included in-class and out-of-school setting practices in the 3rd group was the most effective. This was followed by the 2nd group which included only in-class implementations. The first group which was supported with visuals and theoretical related presented information was the group which was the least effected. The results of the research revealed that pre-service science teachers had mainly different concerns about safety, but that this did not deter them, as they still continued to design curriculum-based field trips for learners.