BACKGROUND Women from South Asia have a high incidence of gestational diabetes mellitus (GDM) placing them at risk of adverse pregnancy outcomes. Despite the higher rates of GDM in this group, there are no studies of their experiences of living with GDM in Australia or elsewhere. OBJECTIVE We aimed to explore the experiences and understandings of South Asian women in Melbourne, Australia, after diagnosis with GDM. METHODS A qualitative approach was used. Face-to-face in-depth interviews were conducted with 17 immigrant women from South Asia recently diagnosed with GDM. They were interviewed in the language of their choice at two time points: in pregnancy after GDM diagnosis and at six weeks postpartum. Thematic analysis was conducted to identify common patterns and salient themes within and across narratives, also taking into account any divergent experiences. RESULTS Before the diagnosis of GDM, women's knowledge and awareness of any diabetes were low. Women and their partners were upset by the diagnosis. Dietary advice received was seen to be challenging in the context of culturally different food habits and consequently managing diet after diagnosis proved difficult. Different attitudes to exercise in pregnancy also raised issues for women. Women said they would try their best to maintain lifestyle modifications postnatally, but were uncertain about sustaining these in the long term. CONCLUSIONS South Asian women require culturally appropriate advice regarding strategies to reduce their risk of GDM as early as possible in pregnancy, ideally at the time pregnancy is confirmed.