Affect recall is key to psychological assessment and decision-making. However, self-concepts (self-beliefs) may bias retrospective affect reports such that they deviate from lived experiences. Does this experience-memory gap apply to solitude experiences? We hypothesized that individuals misremember how they feel overall and when in solitude, in line with self-concepts of introversion, self-determined/not-self-determined solitude motivations, and independent/interdependent self-construal. A pilot study comparing retrospective to daily affect reports captured over 2 weeks (N = 104 UK university students) provided preliminary evidence of introversion and not-self-determined solitude shaping affect recall. In the main pre-registered study, participants aged 18-49 in the UK (N = 160) and Hong Kong (N = 159) reported their momentary affective states and social situations 5 times per day over 7 days, then recalled how they felt over the week. Individuals higher in self-determined solitude were more prone to retrospectively overestimate their high- and low-arousal positive affect in solitude and showed less overestimation/more underestimation of negative affect in solitude. Higher not-self-determined solitude was associated with overestimating loneliness, and higher interdependent self-construal with overestimating loneliness and energy levels, in solitude. Comparisons based on residence/ethnicity suggest culture influences solitude-seeking and affective memory. Implications for well-being and affect measurement are discussed.