The aim of the study was to investigate the effect of constructive and destructive self-talk on the regulation of the performance of elite male swimmers. This quasi-experimental study was conducted using a pretest–posttest design. The statistical population consisted of elite adolescent male swimmers, from among whom 117 elite male swimmers were purposively selected. The participants were then randomly assigned to three groups: constructive self-talk, destructive self-talk, and control. In the pretest stage, the 100-m freestyle swimming time was recorded. On the following day, after instruction on the use of constructive self-talk, including positive and reinforcing statements such as “I can,” and destructive self-talk, including negative and weakening statements such as “I cannot,” the posttest performance of the experimental groups was recorded while using their respective self-talk strategies, and the posttest performance of the control group was recorded again. The data were analyzed using the K–S, ANCOVA, and the Bonferroni test. The findings of the ANCOVA and Bonferroni test showed that although no statistically significant difference was observed in the 100-m freestyle swimming time between the experimental groups and the control group(p>0/05), the difference between the constructive and destructive self-talk groups was statistically significant, such that the performance of the constructive self-talk group was significantly better than that of the destructive self-talk group(p<0/05). It appears that monitoring and preventing the use of destructive self-talk among adolescent athletes and replacing it with constructive self-talk can be used as a more reliable strategy for optimizing the performance of elite swimmers by sports coaches.