Herein, novel photoinduced catalyst-free deborylation–deuteration of arylboronic acids with D₂O is reported. The protocol was compatible with a variety of functionalities, including halogen, alkoxy, cyano, sulfonyl, trimethylsilyl, trifluoromethoxy, alkyl, hydroxyl, free acid, amide, and heteroaromatic rings. A wide range of deuterated products were obtained in good yields with a high level of deuteration. This method provides a green and practical pathway to synthesize deuterium labelled compounds under mild conditions.