Due to a surge in the number of female inmates in England and Wales and Thailand, there is a growing interest in the examination of the experiences of pregnant women and mothers of babies in prison mother and baby units (MBUs) within these jurisdictions. Nevertheless, a comparative approach discussing their experiences in England and Wales and Thailand in a cross-cultural context is still limited. Hence, this study attempts a comparative analysis of the experiences of these prisoners resulting from prison rules in England and Wales and Thailand. By putting on the sociology of imprisonment lens, this study seeks to find their similar and different experiences in MBUs regarding their admission, supports during pregnancy and childrearing, and emotions and relationships to advance understandings of their experiences. It adopts a narrative literature review as the principal research method and selects documents in English and Thai to capture the intricacies of several perspectives. The findings suggest that pregnant women and mothers of babies in MBUs in both jurisdictions share undesirable similar experiences in terms of inappropriate provisions of health, food and nutrition, and living arrangement and desirable similar experiences in terms of relationships they have with babies, prisoners, and prison officers. The findings also indicate that the experiences of these prisoners in England and Wales are different from those in Thailand in terms of admission. In England and Wales, these prisoners experience unpleasant conditions as they undergo assessment while entering MBUs due to limited places, resulting in rejection of applications, whereas these prisoners in Thailand are automictically admitted into MBUs since places are unlimited. The study concludes with reflections on the provision of appropriate supports for these prisoners in both jurisdictions to lessen their undesirable conditions so that they are properly heard, understood, and cared for during pregnancy and childrearing in prisons.