Background Jeddah has the highest international traffic and is among the most diverse cities in Saudi Arabia. The chance of importing an emerging communicable disease is significant, particularly during the religious seasons. Therefore, timely and accurate reporting of communicable diseases at primary health care centers (PHCCs) is crucial. Objectives The main objective of this study was to assess physicians' knowledge, practices, and perceptions of reporting communicable diseases at PHCCs in Jeddah, Saudi Arabia. Methods The study was a cross-sectional study comprising 143 physicians from all PHCCs in Jeddah from October 2017 to February 2018. An electronic questionnaire was used to collect data to assess the physicians' knowledge, practices, and perceptions related to reporting communicable diseases at PHCCs. Results A total of 106 physicians participated in the study. Although only 21.7% of the physicians had received training on reporting communicable diseases, the average knowledge score for the six commonly reported diseases was 72%. More than half (58.5%) of the physicians indicated that they had reported at least one disease. However, there was no agreement on who should be responsible for reporting communicable diseases at PHCCs. Furthermore, some obstacles were perceived that could prevent disease reporting, including physicians not knowing which diseases to report (66%), not knowing how or whom to report to (54.7%), and a limited diagnostic or laboratory capacity (52.8%). Conclusions Reporting communicable diseases at PHCCs was of adequate quality. However, some obstacles must be addressed, and regular applied training must be provided. More extensive assessments are needed to improve the reporting of communicable diseases locally and nationally.