Background: In recent years, there has been a growing interest in the therapeutic potential of classical psychedelics like ayahuasca for mental health improvement. Naturalistic studies at ayahuasca retreats have shown (short-term) improvements in mental well-being but understanding the psychological mechanisms is crucial. We are interested in psychological processes such as resilience, self-compassion, and personality traits. Additionally, it is unclear whether changes are solely due to ayahuasca or influenced by the social setting. To address this, a control group participating in a breathwork session, similar to ayahuasca retreats, was included. Methods: In this observational study, individuals who attended an ayahuasca retreat (n = 69) and individuals who participated in a breathwork session (n = 30) completed an online survey one week before (baseline) and one, six, and twelve weeks after they entered the retreat/session. The survey included a series of questionnaires, i.e., the World Health Organisation-Five Well-Being Index, 14-item Resilience Scale, Self-Compassion Scale–Short Form, and Big Five Inventory-10. A linear mixed model (LMM) was used to analyze the outcome data. Results: It was shown that well-being, resilience, and self-compassion increased and remained stable over 12 weeks compared to baseline, regardless of group (ayahuasca or breathwork). Older participants generally reported higher resilience and self-compassion. Self-compassion was also higher in the ayahuasca group overall. Neuroticism decreased in both groups, with lower scores in the ayahuasca group. Agreeableness increased over time, also not influenced by group membership, while there were no changes in extraversion, conscientiousness, or openness. Discussion: Both interventions improved well-being, aligning with prior research. Importantly, this study unveils a novel finding: both interventions enhance resilience and self-compassion for up to three months, offering promise for conditions marked by low well-being, resilience, and self-compassion like depression and anxiety-related disorders. While acknowledging its limitations (e.g., self-selected sample, no specific information of the ayahuasca brew or the breathwork technique), it emphasizes the need for controlled studies with control groups, attention to social contexts in research on these interventions, and to assess other variables like depth of altered states of consciousness that might explain improvement in psychological processes and wellbeing.