Abstract Background Emergency department (ED) visits due to non-coronavirus disease 2019 (COVID-19) conditions have drastically decreased since the outbreak of the COVID-19 pandemic. This study aimed to identify the magnitude, characteristics and underlying motivations of ED visitors with delayed healthcare seeking behaviour during the first wave of the pandemic. Methods Between March 9 and July 92,020, adults visiting the ED of an academic hospital in the East of the Netherlands received an online questionnaire to collect self-reported data on delay in seeking emergency care and subsequent motivations for this delay. Telephone interviews were held with a subsample of respondents to better understand the motivations for delay as described in the questionnaire. Quantitative data were analysed using descriptive statistics. Qualitative data were thematically analysed. Results One thousand three hundred thirty-eight questionnaires were returned (34.0% response). One in five respondents reported a delay in seeking emergency care. Almost half of these respondents ( n = 126; 45.4%) reported that the pandemic influenced the delay. Respondents reporting delay were mainly older adults (mean 61.6; ±13.1 years), referred to the ED by the general practitioner (GP; 35.1%) or a medical specialist (34.7%), visiting the ED with cardiac problems (39.7%). The estimated median time of delay in receiving ED care was 3 days (inter quartile range 8 days). Respectively 46 (16.5%) and 26 (9.4%) respondents reported that their complaints would be either less severe or preventable if they had sought for emergency care earlier. Delayed care seeking behaviour was frequently motivated by: fear of contamination, not wanting to burden professionals, perceiving own complaints less urgent relative to COVID-19 patients, limited access to services, and by stay home instructions from referring professionals. Conclusions A relatively large proportion of ED visitors reported delay in seeking emergency care during the first wave. Delay was often ...