ObjectiveTo explore views of parents of preterm babies, adults born preterm and professionals, on the linkage of real-world health and education data for research on improving future outcomes of babies born preterm.DesignThree-stage mixed-methods participatory design involving focus groups, a national survey and interviews. Survey participants who expressed uncertainty or negative views were sampled purposively for invitation to interview. Mixed methods were used for data analysis.Setting and participantsAll data collection was online. Participants were: focus groups—17 parents; survey—499 parents, 44 adults born preterm (total 543); interviews—6 parents, 1 adult born preterm, 3 clinicians, 2 teachers.ResultsThree key themes were identified: (1) Data linkage and opt-out consent make sense for improving future outcomes. We found clear demand for better information on long-term outcomes and strong support for data linkage with opt-out consent as a means of achieving this. (2) Information requirements—what, how and when. There was support for providing information in different formats and discussing linkage near to, or following discharge from, the neonatal unit, but not sooner. (3) Looking to the future; the rights of young people. We identified a desire for individuals born preterm to be consulted in the future on the use of their data.ConclusionWith appropriate information provision, at the right time, parents, adults born preterm and professionals are supportive of data linkage for research, including where temporary identifiers and opt-out consent are used. Resources are being co-produced to improve communication about routine data linkage.