This study aimed to determine the best pool size for COVID-19 screening in various risk groups with differing prevalence, using data from February 28 to June 14, 2020, in Iceland. For prevalence scenarios over 0.292, pooling is not more efficient than individual testing due to the number of follow-up tests needed. Pool testing strategies can decrease the number of tests by 61.9% and 54.2% for high-risk groups and 90.2% and 88.5% for low-risk groups depending on test sensitivity (0.71 and 0.98, respectively). For each pooling strategy, as testing sensitivity increases, the number of low-risk individuals screened decreases. Authors suggests that pooled testing will allow more individuals to be screened for COVID-19 while highlighting the importance of determining pool sizes based on risk groups and prevalence in the community.