The two studies included herein discuss mindfulness and acceptance in sport performance. Based on exploratory interviews with elite swimmers, Study 1 showed that optimal performance, or “flow,” states reveal similar characteristics to mindfulness and acceptance states. In flow experiences, the elite swimmers described that they had been particularly mindful of their bodily sensations and accepted them. In Study 2, mindfulness and acceptance were integrated into a psychological skills training program for seven young elite golfers. The program, based on mindfulness and acceptance, contributed to performance enhancement in competition. Participants improved the efficacy of their routines by seeking more relevant internal and external information. The results of both studies corroborated those of previous studies dealing with mindfulness and acceptance in sport. Together, these studies enhance the applicability and efficacy of these approaches with athletic clientele.