Despite al-ʿŪla's arid climate, the earliest sedentary settlement in the wadi dates as far back as the first millennium BC and has been continuously inhabited up to the present day. Rare and short-duration rainfall forced the inhabitants of the wadi to develop several methods to exploit underground water resources. While the well-known qanat network has been partially studied (Nasif 1988), there remains a significant lacuna in the understanding of the wells. The al-'Ūla Cultural Oasis Project (UCOP)-led by Archaïos, funded and steered by the French Agency for Al-Ula Development (AFALULA), on behalf of the Royal Commission for Al-Ula (RCU)-highlighted the study of the wells in its research programme. The preliminary study took place during the autumn of 2020 with a corpus of almost twenty structures detected by remote sensing, followed by a systematic field survey and photogrammetry of a relevant example. This work enabled the establishment of a preliminary typology and a relative chronology of these structures. The study of the distribution of the wells is furthermore essential to the understanding of the spatial development of the oasis.