This study aimed to describe and compare breastfeeding progression, infants' feeding behaviours, maternal feeding difficulties, and mothers' usage of breastfeeding interventions for singleton late preterm (LPT) and term infants. A further aim was to identify associated factors for exclusive breastfeeding at breast at 1 month in LPT infants. This was a cohort study where mothers of LPT infants from a neonatal unit (n = 60), LPT infants from a maternity unit (n = 62), and term infants from a maternity unit (n = 269) answered a questionnaire approximately 1 month after delivery. Findings showed no significant differences in exclusive breastfeeding at breasts between LPT infants admitted to the neonatal unit compared with the maternity unit, during the first week at home (38% vs. 48%), or at 1 month of age (52% vs. 50%). Term infants were more likely to be exclusively breastfed at the breast (86% and 74%, p < 0.05) compared with LPT infants. Multiple regression analysis showed that usage of a nipple shield, not feeding breast milk exclusively during the first week at home, or feeding less than 10 times per day at 1 month were statistically significant for not exclusively breastfeed at the breast. A protective factor was the mothers' experience of having an abundance of milk during the first week at home. In conclusion, LPT infants are less likely to be exclusively breastfed at the breast than term infants, highlighting the need for further research to guide interventions aimed at optimising exclusive breastfeeding rates.