To control the spread of the novel coronavirus disease 2019 (COVID-19), COVID-19 vaccination has been quickly developed. However, the COVID-19 pandemic will not be controlled if the COVID-19 vaccination uptake willingness is low. Therefore, the study aim was to explore the COVID-19 vaccination uptake willingness among the outpatient population and healthcare workers in Taiwan during the worldwide pandemic period without community outbreaks. A cross-sectional survey was conducted among healthcare workers (HCWs; n = 500; mean age = 32.96 years) of National Cheng Kung University Hospital (NCKUH) and outpatients (n = 238; mean age = 34.43 years) arriving at NCKUH. We used an online survey conducted between September 24 and 21 November 2020, for healthcare workers, and between 27 October and 31 December 2020, for the outpatient sample. Information regarding willingness to receive vaccination, willingness to rapid test, fear of COVID-19, risk perception, and preventive behaviors was collected in both samples; information regarding willingness to care for patients was collected in healthcare workers. Willingness to receive vaccination was the main variable in the present study; willingness to rapid test, willingness to care for patients, fear of COVID-19, risk perception, and preventive behaviors were the secondary variables in the study. The factors associated with vaccination willingness were identified through logistic regression analysis. The participants’ willingness to receive vaccination was low for both healthcare workers (23.4%) and the outpatient sample (30.7%). Similarly, their willingness to take rapid tests was low (23.6% for healthcare workers and 28.6% for outpatient sample). Risk perception (crude odds ratio (COR) = 1.29; 95% confidence interval (CI) = 1.03, 1.63), willingness to take rapid test (COR = 9.24; 95% CI = 5.76, 14.83), and preventive COVID-19 infection behaviors (COR = 2.32; 95% CI = 1.52, 3.56) were significant factors explaining the healthcare workers’ willingness to receive vaccination. Willingness to take a rapid test (COR = 8.91; 95% CI = 4.71, 16.87) and preventive COVID-19 infection behaviors (COR = 1.69; 95% CI = 1.09, 2.60) were significant factors explaining the outpatient sample’s willingness to receive vaccination. Willingness to vaccinate against COVID-19 among HCWs and outpatients is low due to the relatively safe status of COVID-19 infection in Taiwan. These findings can help policymakers advocate for the effectiveness of and provide transparent information on COVID-19 vaccination uptake in a country/region with a relatively safe COVID-19 outbreak status.