The discovery of diagnoses and treatments that could save or improve lives requires access to large data sets, but such access has historically been blocked by variations in data security, patient privacy and data interoperability issues globally. Over the course of two years, the World Economic Forum led the Breaking Barriers to Health Data project with genomic institutions in Australia, Canada, the UK and US to create a model to share rare disease data across borders in a federated data system. Allowing access to health data sets is not particularly difficult technically, but larger challenges are explored in this 8-step guide.