There is variation in provision of social care in prisons. Our research aimed to understand variation across adult prisons in England and Wales, including: (1) what social care is provided? (2) who delivers social care? (3) what peer support initiatives are used? (4) what social care indicators are relevant? and (5) are there differences between prison type and social care provision? We analysed Her Majesty’s Inspectorate of Prisons (HMIP) reports (published 2017–2020) from 102 prisons. From these reports we extracted and analysed data on social care provision. Elements of social care are not consistently delivered; need assessments (81.4 per cent) and referrals (75.5 per cent) were most frequently reported. Different providers (health care/social care/prison) deliver social care. Forty-one prisons (40.2 per cent) included peer support (formal to informal). We found no notable differences between prison categories and social care delivery, although, within category D prisons, a significantly larger proportion of those with a disability reported receiving support they needed. Inspection reports highlighted that prison social care should mirror community social care, but we could not fully evaluate this due to reporting issues. Social care provision varies; effectiveness of different models is not yet known. We provide recommendations to improve social care reporting within HMIP reports.