Low levels of concern about anthropogenic climate change have been attributed to a range of factors, some of which relate to education. These include people's lack of understanding and engagement with the multifaceted nature and extent of the problem that it presents to current and future generations. Limited knowledge is also known to be an obstacle to individual behaviour change, with important implications for young people's perceptions of the urgency to act and awareness of the consequences of their own behaviours. In this study, we explored ways to address low levels of understanding about ocean science dimensions to climate change phenomena, cognisant of a growing awareness that formal education curricula do not adequately engage young people with developing ocean literacy. Participants were a sample of secondary school students (11 to 14 years) in Portugal and the UK. Using a gamified mobile application, it was examined relationships between the use of different game elements such as points, badges and leaderboards, and learning outcomes. Systematic evaluation of each element shows how different game features affected the participants' learning experience and learning outcomes. Implications for formal and informal marine education, climate education, and how to improve ocean literacy efforts, are also discussed.