The coronavirus disease 2019 (COVID-19) pandemic has had a profound impact on medical educational curricula. We aimed to examine the impact of these unprecedented changes on the formal education of paediatric cardiology fellows through a nationwide survey. A REDCap™-based voluntary anonymous survey was sent to all current paediatric cardiology fellows in the United States of America in May, 2020. Of 143 respondents, 121 were categorical fellows, representing over one-fourth of all categorical paediatric cardiology fellows in the United States of America. Nearly all (140/143, 97.9%) respondents utilised online learning during the pandemic, with 134 (93.7%) reporting an increase in use compared to pre-pandemic. The percentage of respondents reporting curriculum supplementation with outside lectures increased from 11.9 to 88.8% during the pandemic. Respondents considered online learning to be “equally or more effective” than in-person lectures in convenience (133/142, 93.7%), improving fellow attendance (132/142, 93.0%), improving non-fellow attendance (126/143, 88.1%), and meeting individual learning needs (101/143, 70.6%). The pandemic positively affected the lecture curriculum of 83 respondents (58.0%), with 35 (24.5%) reporting no change and 25 (17.5%) reporting a negative effect. A positive effect was most noted by those whose programmes utilised supplemental outside lectures (62.2 versus 25.0%, p = 0.004) and those whose lecture frequency did not decrease (65.1 versus 5.9%, p < 0.001). Restrictions imposed by the COVID-19 pandemic have greatly increased utilisation of online learning platforms by medical training programmes. This survey reveals that an online lecture curriculum, despite inherent obstacles, offers advantages that may mitigate some negative consequences of the pandemic on fellowship education.