In March 2020, the Belgian government ordered a complete lockdown as an attempt to decrease the progression of the COVID‐19. The aim of the present study was to examine lockdown‐related changes in psycho‐affective states as well as their relations with experiential diversity and autobiographical memory. A total of 186 Belgian citizens completed an online survey assessing lockdown‐related changes in various dimensions: work, leisure activities, affective state, sleep quality, fatigue, and autobiographical memory. Results revealed that well‐being during the lockdown was related to changes in experiential diversity and to the richness of participants' memories. Moreover, the content and the phenomenology of memories were more negative when memories pertained to the lockdown situation. These findings provide new evidence that mental well‐being of Belgian citizens during the first lockdown was related to how pandemic‐related sanitary constraints affected the diversity of activities that they could undertake. [ABSTRACT FROM AUTHOR]