The hamadryas baboon (Papio hamadryas hamadryas) is the only indigenous species of non-human primates (NHP) found in the Kingdom of Saudi Arabia (KSA). There are no peer-reviewed publications on viral infections of the baboons of KSA. Apart from camels, other animals are likely sources of the novel Middle East Respiratory Syndrome coronavirus (MERSCoV) for humans. We investigated evidence of highly pathogenic coronavirus infections including MERSCoV in a large group of commensal baboons accompanied by feral dogs, on the outskirts of Ta'if city, KSA, in February 2013. Fifty baboons (16 juveniles and 34 adults) were screened for serum antibodies to human coronaviruses (HCoV-043/-NL63/-229) and canine coronaviruses (CCoV-1-3) using direct Enzyme-linked Immunosorbent Assay (ELISA) technique and for MERSCoV antibodies using Serum Neutralization Test (SNT). Of the 50 sampled baboons, 22% (n = 11) were seropositive to HCoVs, 10% (n = 5) were seropositive to CCoVs, while none had detectable MERSCoV antibodies. These findings bear potentially significant implications for public health, canine health and baboon conservation efforts, necessitating follow-up investigations and preventive measures at locations where baboons frequent human habitations, or are regarded as tourist attractions, in KSA.