Abstract Background Adolescent mothers have lower rates of initiation, continuation, and exclusivity of breastfeeding, and even more so in the first pregnancy. Current interventions target adult women, and little evidence is available for breastfeeding promotion among adolescents. Methods This is a pilot study protocol with a parallel, single-blind, randomized, and controlled trial design, to evaluate the feasibility of the intervention “Lactation Counseling” in first-time adolescent mothers to maintain exclusive breastfeeding in the first 6 months of life. The control group will receive routine education in prenatal care and prenatal and childbirth classes, the experimental group will receive additionally the intervention “Lactation Counseling”, for 4 weeks, both conducted by trained nurses. Feasibility outcome includes recruitment and dropout rates, and, pilot outcomes will be the exclusive breastfeeding rate and the breastfeeding knowledge. Measurements will be taken at baseline, post-intervention, and 2, 4, and 6 months after childbirth. Discussion Exclusive breastfeeding rates could be increased in adolescent mothers through nursing counseling interventions that are previously structured and evaluated from their feasibility. This study will allow the evaluation of the feasibility of an intervention in low-income, Latin American population adolescents. Trial registration ClinicalTrials.gov NCT04655846 , Registered 7 December 2020.