Preconception bariatric surgery improves obesity-related maternal pregnancy complications but may reduce the absorption of nutrients required for healthy fetal growth and development. Women who receive preconception nutritional support after bariatric surgery are less likely to have adverse pregnancy outcomes. This study aimed to investigate the provision of preconception and pregnancy-specific nutritional support for women having bariatric surgery in the UK. A mixed-methods survey was distributed to healthcare professionals working in obesity or maternity services between December 2018 and October 2019. We collected both quantitative and qualitative data which were analysed using a mixed-methods approach. We received 135 responses from online (n = 99) and postal (n = 36) questionnaires. Only 45% of participants reported being 'very familiar' with the preconception/pregnancy nutritional needs of this population. Barriers to providing nutritional support included: a lack of resources and time; poor communication both across services and with women; not having contact with women preconception; and a lack of information and guidance. Respondents felt that dietitians have the expertise in nutrition necessary to provide support; however, GPs and midwives have the most frequent patient access post-surgery, both before and during pregnancy. Optimal preconception and pregnancy-related nutritional support requires multidisciplinary care pre- and post-surgery, and healthcare professionals require training and guidance to inform practice.