Geographical regions have a major effect on the arrival times of different insect species on carrion. This means that data generated in one region should not be used to determine time of death in a different region. In the present study, we demonstrate the effect of geographical location on the diversity of carrion beetles in Saudi Arabia, whereas the mitochondrial cytochrome c oxidase subunit I (mtCOI) barcodes were used as a marker for molecular identification of the carrion beetles at a dry stage on sheep carrion. We analyzed 819 adult beetles belonging to nine species originating from Riyadh (609 beetles), Jazan (157 beetles), and Arar (53 beetles). In Riyadh, results showed the presence of six species belonging to three different families. On the other hand, in Jazan five species belonging to four families were collected. From Arar, five species belonging to three families were collected. By comparing between individuals of the same species from different regions, individuals of Necrobia rufipes DeGeer (Coleoptera: Cleridae) showed the highest intraspecific variations 0–20%, while individuals of Saprinus splendens Paykull and Saprinus semistriatus Scriba (Coleoptera: Histeridae) showed the lowest intraspecific variations 0–1%. Interspecific variability was also measured between collected and identified species, with differences revealed to be in the range of 3.8–29.8%.The results are important from an ecological point of view and for Medico-Legal Forensic Entomology.