ABSTRACT Background: The impact of cancer extends beyond treatment and evaluating the adverse psychological effects in survivors is important. We examined: (1) the relationship between diagnosis, relapse, and subjective well-being using a short and a holistic measure of well-being, including comparisons between our sample and established norms; (2) if reported physical symptoms were related to components of subjective well-being; and (3) if increased psychological flexibility predicted overall subjective well-being. Methods: In total, 316 survivors completed online questionnaires to assess cancer, physical health (Edmonton Symptom Assessment Scale-R; ESAS-R), subjective well-being (Comprehensive Inventory of Thriving; CIT; Satisfaction with Life Scale; SWLS) and psychological flexibility (Comprehensive Assessment of Acceptance and Commitment Therapy). Results: Relative to ESAS-R cut-points (Oldenmenger et al., 2013), participants reported only moderate levels of tiredness and slightly elevated drowsiness, depression, and anxiety; participants reported more problems with psychological health. SWLS scores were lower than published norms (M = 18.23, SD = 8.23) and a relapse was associated with the lowest SWLS scores (M = 16.95, SD = 7.72). There were differences in thriving between participants and age-matched norms (Su et al., 2014). Participants reported lower community involvement, respect, engagement with activities, skill mastery, sense of accomplishment, self-worth, self-efficacy, autonomy, purpose, optimism, subjective well-being, and positive emotions coupled with higher loneliness and negative emotions. In regression analysis, two components of psychological flexibility, Openness to Experience, t = 2.50, p < 0.13, β = −0.18, and Valued Action, t = 7.08, p < 0.001, β = −0.47, predicted 28.8% of the variability in total CIT scores, beyond the effects of demographic and disease characteristics and reported physical symptoms. Conclusion: Cancer is an isolating experience, with the adverse psychological effects that impact subjective well-being continuing after the cessation of physical symptoms. Specific components of psychological flexibility may explain some variability in thriving beyond disease characteristics and may inform psychological intervention after diagnosis.