People with serious mental illness (SMI) such as schizophrenia, schizoaffective disorders and bipolar disorder are at increased risk of developing diabetes, cardiovascular disease and respiratory disease, contributing to significantly reduced life expectancies. As a result, emphasis has been placed on developing Health Promotion Programmes (HPPs) to modify the risk of poor physical health in SMI. We examined how many and what types of HPPs are available for or inclusive of people with SMI across four borough in South London, UK. A cross-sectional mapping study was carried out to identify the number of HPPs available to people with SMI. We found 145 HPPs available to people with SMI existed across the four boroughs but with an inequitable distribution, which in some boroughs we anticipate may not meet need. In some cases, HPPs set admission conditions which were likely to further impede access. We recommend that accurate and readily available information on the provision of HPPs for or inclusive of people with SMI is needed.