BackgroundThe novel coronavirus disease has emerged as the most pressing global health issue. In women with COVID-19 disease, pregnancy confers a substantial additional risk of morbidity and mortality.ObjectiveThis study aimed to assess WHO-recommended COVID-19 prevention practices and determinant factors among pregnant women attending antenatal care during the third wave of COVID-19 in eastern Ethiopia.MethodsAn Institutional-based cross-sectional study was conducted among 422 pregnant women attending antenatal care in Harar, from October 10 to November 10, 2021. The sample size was proportionally allocated to all healthcare facilities, then the study participants were selected using systematic random sampling. Descriptive summary statistics were done. Logistic regression analyses were computed to identify associations between dependent and independent variables. Variables with a p-value < 0.05 were declared statistically significant.ResultOut of 422 pregnant women, 61.6% of them had good WHO Recommended COVID-19 Prevention Practices. Those with age 25–34 years (AOR: 9.7, 95%CI: 4.8, 19.3), age 35–44 years (AOR:4.8, 95%CI: 2.6, 9.03), monthly income > 10,000 ETB (AOR: 9.4, 95%CI: 2.1, 42.1), being a student (AOR: 10, 95%CI: 2.3, 47.1), having a good level of knowledge (AOR: 2.3, 95%CI:1.4, 3.8), and having ≥10 family members (AOR: 0.24, 95%CI: 0.06, 0.9) were found to have a significant association with WHO recommended prevention practice among pregnant women.ConclusionOverall, the WHO-recommended COVID-19 prevention practice among pregnant women attending antenatal care was good, but it needs improvement. In order to improve prevention practices among pregnant women, Harari Regional Health Bureau and other stakeholders should provide repeated, targeted, and tailored information to pregnant women and the community at large through different media.