Flow is a state of optimal experience in which people get fully absorbed by a smoothly running activity that they pursue for the sake of it. Based on the classical approach to motivation, recent theoretical considerations suggest that incentives provided by the current activity that are congruent with one’s implicit motives will lead to flow. In a field experiment, we examined wall climbers’ achievement motive and compared their flow on four climbing routes with varying achievement incentive strengths. Only climbers with a high achievement motive experienced more flow after repeating an intra-individually skill exceeding route, which they had failed before. Performing better was a strong achievement incentive. The findings suggest that motive incentive congruence is another important precondition for flow.