PURPOSE: To explore the relationship among cognitive emotion regulation strategies, psychological flexibility, and subjective well-being, analyze the latent profiles of cognitive emotion regulation strategies, and examine the mediating role of psychological flexibility between cognitive emotion regulation strategies and subjective well-being in patients with breast cancer. METHODS: The cross-sectional study was conducted from April to December 2023, involving 313 patients with breast cancer. The Cognitive Emotion Regulation Questionnaire-short, the Acceptance and Action Questionnaire-II, and the Index of Well-Being were utilized for data collection. Descriptive statistics, Pearson's correlation coefficient, latent profile, Bayesian factor, and mediation effect were used for data analysis. RESULTS: There was a small to strong correlation among the variables. Latent profile analysis revealed three potential profiles of cognitive emotion regulation strategies, named "low copers", "high copers", and "flexible copers", respectively. Compared with the "flexible copers" group, psychological flexibility might potentially mediate the relationship between the "low copers" profile and subjective well-being, as well as between the "high copers" profile and subjective well-being, with relative indirect effects of -0.720 (95%CI: -1.104, -0.387) and -1.216 (95%CI: -1.732, -0.711), respectively. CONCLUSION: The results examined the relationship among variables, identified three distinct profiles of cognitive emotion regulation strategies, and indicated that psychological flexibility might serve as a potential mediator between cognitive emotion regulation strategies and subjective well-being.