The Deep-time Digital Earth (DDE) programme of the International Union of Geological Sciences (IUGS) has been developed to address the formidable challenge of so called ‘long tail’ data in the geosciences - the unstructured and inherently heterogeneous geoscience data that resides in institutions, universities and on individual geoscientists’ computers. DDE’s vision is to transform Earth science by connecting and harmonising long tail deep-time data ‘islands’ to support broad-based scientific studies relevant to the entire Earth system. The results of these and other studies will help us understand Earth’s natural environment and help in the wise use of natural resources for the prosperity of nations and the quality of human life. This harmonisation is now possible through the digital revolution, but new protocols, platforms and programs are needed to secure compatible and interoperable databases, so that the vast amounts of existing (and new) deep-time geoscience data can be linked. Since the first DDE meeting in January 2019, great progress has been made in defining statutes and byelaws, governance structures and preliminary informatics and scientific aims.