Longer intended duration of breastfeeding, sustaining breastfeeding-friendly practices after discharge, and maintenance of a higher level of breastfeeding self-efficacy were the determinants of breastfeeding at 4 and 6 months. Healthcare professionals in Taiwan must support breastfeeding-friendly practices and consider interactive interventions to promote continued breastfeeding at different stages during the first 6 months after childbirth on the basis of the mother's breastfeeding plan and breastfeeding self-efficacy during their postnatal hospitalization.