Background Debate about mother and infant bed sharing has been polarized between supporters of bed sharing and public health policies that attempt to mitigate the risk of Sudden Infant Death Syndrome. Differences in group demographics may be an important aspect in co-sleeping acceptability. Research aims The first aim of this study was to investigate infant sleeping location in a dataset of mothers with strong breastfeeding outcomes. The second aim was to investigate the association between infant sleeping location and breastfeeding (exclusive breastfeeding to 6 months and total breastfeeding duration). Finally, we aimed to investigate predictors of breastfeeding duration. Methods Participants comprised 174 women who had applied to train as counselors with the Australian Breastfeeding Association. Data were compiled from a survey of the participants’ lactation histories, including questions related to the exclusivity and duration of breastfeeding, concerns about and problems encountered during breastfeeding, type of birth, medications during birth, demographics, and infant sleeping location. The study design was a cross-sectional, one-group survey design. Results A high proportion of participants in this study bed shared and room shared: At 0–1 month ( n = 58), 33% of participants bed-shared, which increased to 58% by 6–12 months ( n = 80). Infants who co-slept were more likely to be exclusively breastfed at 6 months (χ² (2, n = 116) = 4.83, p = .03) and had longer breastfeeding duration ( t (62.61) = 3.81, p < .001). Conclusions Breastfeeding targets have been difficult to achieve globally, and innovative ideas are required to improve breastfeeding outcomes through public health messaging. There was a strong association in the current study between breastfeeding outcomes and degree of closeness of the infant to the mother at night. This finding should be brought into the discourse on breastfeeding and infant sleep arrangements, accompanied by evidence-based advice about safe sleeping and the promotion of breastfeeding.