We present the findings from a mixed-methods evaluation focused on measuring longer-term student outcomes from the Ocean Guardians Workshop (OGW). The OGW is a two-day, Ocean education program for 11–13-year-old underserved students in western Cape Town, South Africa. The OGW incorporates beach clean-ups, ecosystem explorations, snorkeling, mindfulness approaches, and more. We used pre-, post-, and follow-up surveys developed with the organization to measure outcomes related to Ocean Learning, Attitudes Towards the Ocean, and Ocean Stewardship Behaviors for 266 students that attended the OGW. Our findings suggest positive short-term and longer-term gains across many of these student outcomes. Particularly noteworthy outcomes include positive changes in student’s attitudes towards the Ocean, which persisted months after the program, along with over 70% of students reporting performing one or more Ocean stewardship behaviors in the four months after the OGW. This study helps to fill a gap in measuring diverse, and longer-term, student outcomes. In this chapter, we share details on the collaborative nature of this evaluation study, findings from these efforts, and future directions.