Roughly 70 locations across 18 Saudi cities appear on the stores page. Most are in Jeddah, Riyadh, Madinah and Makkah; the rest are in Abha, Jazan, Tabuk, Hail, Buraidah, Khamis Mushait, Taif, Arar, Dammam, Al Khobar, Jubail, Al-Ahsa, Khafji and Hafar Al-Batin. Outside the Kingdom, Osma has stores in Bahrain, Qatar, the UAE, Oman and Kenya.
Keep in mind that the return policy does not allow website orders to be returned in a store, and the site says nothing about return terms for in-store purchases, so ask at the store at the time of purchase. Osma's app is available on Google Play and the App Store, with links in the site footer.
Source: Osma Perfumes: our stores