Background: Being a mother of a preterm infant (< 37 gestational weeks) puts the mother in a vulnerable andfragile situation wherein breastfeeding is an important part of becoming a mother and bonding with the infant.Nevertheless, the breastfeeding experience of mothers during the first year after a preterm birth has not been wellstudied. To develop professional caring and supporting relationships, it is important to address this knowledge gap.The aim of this study was to describe the breastfeeding experience of mothers of preterm infants from birth upuntil 12 months after birth.Methods: The data in this qualitative study are derived from a multicentre randomized controlled trial where 270mothers of preterm infants provided 496 written comments through questionnaires containing open-endedquestions. The questionnaires were sent to the mother three times during the first 12 months after birth. Athematic network analysis based on hermeneutical philosophy was used to analyse and interpret the resulting datato describe the mothers’ experiences of breastfeeding.Results: Three organizing themes, namely, “navigating smoothly,” “navigating with a struggle” and “navigating inambiguity” were revealed in the mothers’ narratives regarding their breastfeeding experiences during the first 12months after birth. These organizing themes were further interpreted as one global theme that was deemed “Ajourney to finding one’s unique way in breastfeeding.”Conclusion: Mothers of preterm infants are in an exposed and vulnerable situation when initiating breastfeedingduring the first year. This situation leads to a unique journey wherein each mother navigates through breastfeedingdepending on her individual situation. An awareness of the diversity of breastfeeding experiences may contributeto the provision of professional caring and supportive relationships.