This article reports on a study that investigates the effects of inter-cultural contact on flow experiences during the performance of five oral tasks in an English as a foreign language (EFL) classroom. Using a quasi-experimental design, Japanese EFL learners in the inter-cultural group (n = 21) and the intra-cultural group (n = 21) reported on their perceptions of task experiences for each performance. Under the intra-cultural condition, learners performed tasks with Japanese peers, whereas under the inter-cultural condition learners were paired with non-Japanese international students. The dimensions of flow, as they emerged in the data, were identified via a content analysis of 208 diary entries. The findings revealed that inter-cultural task interaction generated significantly more flow-enhancing experiences and fewer flow-inhibiting experiences than intra-cultural task interaction. An examination of the relative strength of each dimension revealed that learners experiencing inter-cultural task-based interaction benefited from a sense of accomplishment, which increased in strength as learners progressed through the tasks. Results provide insights into how components of flow are interrelated and change over time during inter-cultural interactions, and suggest a model for how tasks can be implemented in the classroom to promote certain aspects of flow.