Objective To compare and analyze the differences in the sociodemographic and clinical characteristics of suicide attempters who visited an emergency department (ED) before and during the coronavirus disease (COVID-19) pandemic.Methods This single center, retrospective study was conducted by reviewing the medical records of patients in the “self-injury/suicide” category of the National Emergency Department Information System who visited an ED between January 2019 and December 2020. We obtained information on baseline characteristics, suicide attempt, and disposition. Data were analyzed using the chi-squared test.Results A total of 456 patients were included. The number of patients visiting the ED for suicide attempts increased by 18.2% (from 209 to 247 cases) during the COVID-19 pandemic, and the ratio of suicide attempters to the total number of ED visits increased by 48.8% (from 0.43% to 0.64%, P<0.001). There were significant differences in methods of suicide attempt, endotracheal intubation, ED disposition, and the presence of mental illness. Drug overdose (42.1% vs. 53.4%) and gas inhalation (5.7% vs. 8.5%) increased, and hanging decreased (6.0% vs. 2.0%) during the pandemic. Endotracheal intubation (13.9% vs. 5.7%) and intensive care unit admission (29.7% vs. 14.6%) decreased. More patients with the history of mental illness visited during the pandemic (54.0% vs. 70.1%).Conclusion Since the COVID-19 pandemic began, suicide attempts have increased in this single ED although the lethality of those attempts is low.