Mindfulness is growing in popularity with the potential to improve many favorable health outcomes. Physical activity (PA) is crucial for improving health, however, there is no Turkish scale to measure mindfulness during PA. The purpose of this study was to translate, culturally adapt, and validate the Turkish version of The State Mindfulness Scale for Physical Activity (SMS-PA-T). One hundred thirty-seven young adult athletes were included. The validity was determined using the Behavioral Regulation in Exercise Questionnaire--2 (BREQ-2) and the International Physical Activity Questionnaire--Short Form. The SMS-PA-T had a high-level internal consistency ([alpha] = 0.80) and test-retest reliability (ICC = 0.61 to 0.72 for subscales). The SMS-PA-T subscales were correlated with the BREQ-2 (r = 0.65 to 0.77, p < 0.005) indicating a good concurrent validity. The results show that the SMS-PA-T proved to be a valid and reliable scale for young adult athletes. The SMS-PA-T provides an easy-to-administer and useful tool to assess.