Background Children were thought to be immune to the COVID-19 pandemic or have a mild form of the disease. However, reports showed multiple cases of post-COVID-19 inflammatory shock syndrome, later known as the multisystem inflammatory syndrome in children (MIS-C). Although rare, it remains an important cause of morbidity and mortality in pediatric COVID-19 patients. Objective To assess the prevalence and characteristics of cardiac manifestations (clinical, radiological, and laboratory findings) of post-COVID-19 MIS-C admitted to the main tertiary hospital in Manama, Bahrain, and to compare such characteristics with regard to age and sex. Methods A retrospective study was conducted at a tertiary hospital in Manama City, Bahrain. Data were collected from the hospital's medical records system. All pediatric patients who were admitted during the period from April 2020 to September 2021, with the diagnosis of post-COVID-19 multisystem inflammatory syndrome in children, were included. The percentage of cardiac manifestations and subgroup analyses were calculated based on age and sex. Results Data from 38 children who were diagnosed with post-COVID-19 multisystem inflammatory syndrome in children were analyzed. Among these cases, cardiac manifestations were found to be prevalent, specifically relating to valvulopathies such as mitral valve insufficiency (42.1%) and tricuspid valve insufficiency (31.6%). Children over the age of six exhibited a higher prevalence of cardiomegaly. Females had a greater prevalence of mitral valve insufficiency and cardiomegaly, while males showed a higher prevalence of coronary artery dilatation, pericardial effusion, and tricuspid valve insufficiency. Conclusion The study emphasizes the frequent occurrence of cardiac manifestations in MIS-C. As this is a single-center study, the findings cannot be generalized. However, it underscores the importance of assessing the disease's impact during the initial presentation, throughout the clinical course, and during the follow-up post-recovery.