Despite growing evidence that women with bipolar disorder (BD) diagnoses are at a particularly increased risk for perinatal mental and physical health complications, our understanding of their experiences and support needs from pre-conception to early postnatal years is still in its early stages. To address this gap, a qualitative study was carried out employing a constructivist grounded theory approach to identify the underlying processes shaping women’s journeys to motherhood in the context of BD. In-depth, semi-structured online interviews were conducted with 10 mothers worldwide with a pre-existing diagnosis of BD and a first child under 5 years of age. Mothers’ experiences revolved around a constant interplay between vulnerability and adaptability, leading to the development of the substantive theory of adaptability as a journey. This study proposes that becoming adaptable constitutes a process, with the concept of “projecting adaptability” being influential in this journey. Characterized by the interconnected elements of self-awareness of vulnerability, perceived support from external sources, and ownership of experiences, the ability to envision an adaptable version of oneself along with understanding the path to achieving it played a significant role in women’s experiences. Overall, there is a need for a more dynamic understanding of these experiences, providing appropriate support rather than viewing women as simply vulnerable or adaptable. Further research is necessary to explore the transferability of this theoretical framework, especially among mothers from diverse socio-economic backgrounds.