The UK Marine Area extends over some 867,400 km2, an area equivalent to around 3.5 times the UK terrestrial extent. The UK's marine heritage is extraordinarily rich and exciting. Wrecks on the sea bed range in date from the Bronze Age to the World Wars and bear testimony to Britain as an island nation, a destination for trade and conquest, and in past times, the heart of a global empire. Communities along the coast have been shaped by their maritime heritage and monuments and stories recall losses and heroes. Much further back in time, before the Bronze Age, a great deal of what is now the North Sea was dry land, peopled by prehistoric communities who lived in lowland landscapes, some on very different coastlines. The British Isles would have been distant uplands above hills and plains and rivers. This arc of heritage, stretching over 23,000 years, is represented by an abundance of collections. Charts and maps, documents, images, film, oral histories, sonar surveys, seismic data, bathymetry, archaeological investigations, artefacts and objects, artworks and palaeoenvironmental cores all tell us different things about our marine legacy. But they can't easily be brought together. They are dispersed, held in archives, unconnected and inaccessible. This matters because it is clear that the story of our seas is of huge interest to the UK public. In 2019 alone, there were 2.9m visits to Royal Museums Greenwich, home of the National Maritime Museum; 1.1m visits to National Museum Royal Navy; 837,000 visits to Merseyside Maritime Museum, and 327,000 visits to HMS Belfast. It is also clear that our exploitation of our seas is increasing dramatically. Windfarms, mining, dredging for aggregates, port expansions, leisure and fishing are all placing tensions on the survival of our heritage. If we are to unlock new stories and manage our past effectively and sustainably, we need to join up all our marine collections and get the most of them. UNPATH will bring together first class universities, heritage agencies, museums, charitable trusts and marine experts to work out how to join these collections up. It will use Artificial Intelligence to devise new ways of searching across newly linked collections, simulations to help visualise the wrecks and landscapes, and science to help identify wrecks and find out more about the artefacts and objects from them. It will deliver integrated management tools to help protect our most significant heritage. And it will invite the public to help co-design new ways of interacting with the collections and to help enhance them from their own private collections. The methods, code and resources created will be published openly so they can used to shape the future of UK marine heritage.