Many preservice primary teachers initially have a low self-efficacy, or belief in their ability to teach science, but well-designed science education courses can produce significant positive changes in efficacy beliefs. However, the extent to which the belief changes are durable, or maintained over time, is yet to be established. The purpose of this study was to investigate the durability of changes in preservice primary teachers' self-efficacy beliefs. Their science teaching self-efficacy was measured at the beginning and end of a science methods course, and then after a delay period of 9 months. Interviews were carried out 1 year after the end of the course. The results indicated that positive changes in self-efficacy occurred as a result of the course, and these high levels were still present after the delay period. Having an opportunity to teach science in primary school was a significant factor in consolidating efficacy levels after the methods course. (Contains 3 tables.)