Background: Maternal overweight is increasing, and it is associated with several risks for both the mother and child. Healthy lifestyle behaviors adopted during pregnancy are likely impact women’s health positively after pregnancy. The study’s aim was to identify and describe weight management behaviors in terms of the Capability, Opportunity and Motivation Behaviour (COM-B) -model to target weight management interventions from the perspectives of overweight women and maternity care professionals. Methods: This qualitative, descriptive study was conducted in 2019–2020. Individual interviews of overweight pregnant and postpartum women (n = 11) and focus group interviews of public health nurses (n = 5) were undertaken in two public maternity clinics in Southwest Finland. The data were analyzed using deductive content analysis consistent with the COM-B model.Results: In the capability category, overweight women and public health nurses thought that there was a need to find consistent ways to broach overweight, which had become a part of women's identities. The use of health technology was considered as a part of antenatal care to broach the subject of weight and weight management. Smart wearables could also support evaluating overweight women’s lifestyles. The opportunity category highlighted a lack of resources for support in perinatal care, especially after birth. Support from family was the most important facilitating factor besides motivation. There was a conflict between pregnancy as an excuse to engage in unhealthy habits and pregnancy as a motivational period during which to change one’s lifestyle. Furthermore, the women wanted a tough stance on weight management and discreet counseling.Conclusions: Our findings offer a theoretical basis for tailoring, testing and implementing interventions that address barriers to effective weight management. Such interventions should offer clear advice and non-judgmental support during pregnancy and after delivery by targeting women’s capabilities, opportunities, and motivation. Health technology could be a valuable component of intervention, as well as an implementation strategy, as it provides ways to broach this topic and support overweight women during maternity care.