This multimethod study is an exploration of the validity and interpretive utility of Dörnyei’s (2009) ‘L2 motivational self-system’ (L2MSS), as it applies to adult, non-formal learners of Irish, who are learning through Massive Open Online Courses (MOOCs). It is grounded in the psychology of language learning motivation (LLM), assessing whether non-formal adult Irish L2 learners are motivated by future L2 guides, both Ideal, reflecting hopes and dreams, and Ought-to, representing obligations and responsibilities. Three research questions are addressed, i) exploring the theory’s validity at a general level and examining whether ii) the L2 learning experience and iii) learner heritage background, are meaningful in predicting, and understanding, the motivations of learners. Using distinct samples from an iterated quantitative survey instrument (final n=638) and narrative interviews (n=42), evidence demonstrates the theory’s utility in an underexplored context, while raising questions regarding adult Irish language learners and theories of self. Learners endorsed and articulated internalised reasons to learn, encompassing personal hopes and obligations, with social others less directly impactful on their motivation. The futures learners described often referenced non-L2 related aspirations of self, and were less-directly related to L2 proficiency, in many cases. Challenges in relation to the latter, due to contextual difficulties, low efficacy beliefs, and limited contact with L2 speakers and learners, are described. Recommendations to encourage sustained L2 learning and support adult learners in fostering and developing L2 selves are made, to aid them in realising their personal language learning goals.