Unit 731, a biological warfare research organisation that operated under the authority of the Imperial Japanese Army in the 1930s and 1940s, conducted brutal experiments on thousands of unconsenting subjects. Because of the US interest in the data from these experiments, the perpetrators were not prosecuted and the atrocities are still relatively undiscussed. What counts as meaningful moral repair in this case-what should perpetrators and collaborator communities do decades later? We argue for three non-ideal but realistic forms of moral repair: (1) a national policy in Japan against human experimentation without appropriate informed and voluntary consent; (2) the establishment of a memorial to the victims of Unit 731; and (3) US disclosure about its use of Unit 731 data and an apology for failing to hold the perpetrators accountable.