Abstract Objectives Sri Lanka has been awarded the first-ever ‘Green’ breastfeeding (BF) nation status by the World Breastfeeding Trends Initiative (WBTi) in January 2020. Our objective was to explore the maternal perceptions of unrevealed barriers for the provision of promotion, protection and support of optimal exclusive breast feeding (EBF) up to six months. Methods We used in-depth interviews with 16 mothers with infants completed six months, who had been unable to practice EBF, attending six child-welfare clinics in Anuradhapura, Sri Lanka. Initial thematic analysis built upon force field and social learning theories were conducted to identify the barriers for optimal EBF practices during the first six months life. Results Main challenges to EBF were notably clustered at three occasions over the six months and first during the first 2–3 days after the delivery. Factors related to child birth influencing self-efficacy and confidence on establishing breastfeeding included cesarean section, pain and poor positioning due to pain, exhaustion, and perceived “inadequate milk”. Suboptimal policies on ward environment and practice of health staff that could lead to maternal worry and maternal stress related to demand for EBF were also identified as key barriers. Despite the early challenges, mothers who interrupted EBF within the first few days, desired to go back to EBF and was able to do so. The second occasion of cessation of EBF occurred around 2–3 weeks postpartum by introducing water or infant formula. These mothers lacked family support for BF leading to physical and mental exhaustion. Additionally, the mother's perception that “healthy infants should be chubby” also led to introduction of infant formula. On-demand feeding was reported to be a challenge due to misconceptions such as feeding according to a time table. Working mother reported ending EBF between 4 and 5 months, and they lacked self-efficacy, resulting from the lack of enabling environments and social support to express and continue only breast milk. Conclusions Although Sri Lanka has attained the “green” breastfeeding top status, interventions are needed to better the support the BF needs of mothers after cesarean section and to practice on-demand feeding and to improve the support for mothers that are employed in order to optimize EBF until completion of six months. Funding Sources No funding source.