Mastering pediatric echocardiography (PE) requires a substantial knowledge base of echo theory and congenital heart disease (CHD), along with technical proficiency. Online self-directed learning has become increasingly utilized among medical trainees to promote competency within medical subspecialties. We sought to evaluate the impact of online learning combined with lecture-based and hands-on teaching on the acquisition of PE knowledge and confidence in pediatric cardiology and pediatric critical care fellows. We prospectively enrolled 124 learners from 2016 to 2019. These included 40 incoming cardiology and critical care fellows at Texas Children’s Hospital (TCH) as well as 84 national and international participants recruited from our online echo education website. All participants completed online learning modules through our website (www.​pedecho.​org), which covers pediatric echo physics, Doppler, technique, normal anatomy, atrial septal defects, and ventricular septal defects. TCH cardiology and critical care fellows subsequently participated in an Echo Boot Camp (BC), a 3-day training program with hands-on workshops and didactic lectures. Knowledge was assessed using an 80-question pre and post-test multiple choice exams. The online learning group demonstrated improvement in exam scores following online learning (PRE 49.1 ± 15.3 vs. POST 67.8 ± 17%; p ≤ 0.01). Echo Boot Camp fellows were noted to have further incremental improvement in test scores following BC (PRE 48% ± 13% vs. POST MODULE 68.6% ± 15% vs. POST BC 75.7% ± 13%; p ≤ 0.01). Self-assessment regarding confidence in context areas showed a substantial gain in self perceived interpretive confidence across all groups as well as procedural confidence in BC participants. Online learning significantly promotes the acquisition of echocardiography knowledge. Additional lecture-based and hands-on teaching in the form of an Echo Boot Camp can further enhance knowledge and interpretative skills. Both of these learning platforms appear to work in concert as powerful and effective tools in fellow education.