Flow has been identified as an optimal state of total immersion, enjoyment, and concentration with the appropriate balance of challenge and skills (Csíkszentmihályi, 1990) and an important factor contributing to improved task performance (Gregersen & MacIntyre, 2014). However, despite its relevance, publications related to this aspect in the context of foreign language (FL) geragogy (i.e., FL learning and teaching of older adults), are still very scarce. To bridge this gap, the present research was undertaken with older adult English as a FL learners aimed at investigating task-specific flow and the corresponding range of emotions. The study employed a mixed-methods approach with two types of data collected in two stages. First, students of the University of the Third Age, representing A1 (n = 20) and A2+ (n = 18) proficiency levels (Council of Europe, 2001), were asked to complete a questionnaire after performing three different tasks during a regular lesson: a listening task, a grammar exercise, and an information gap speaking activity. The data collection instrument tapped into their enjoyment, anxiety, and flow. This was followed by semi-structured interviews with selected participants (n = 9). The results show that flow in the FL classroom is dynamic, and dependent on specific task characteristics, especially the arrangement mode and the level of other students' disruptive behaviors.