The Belfast–Larne line, or Larne line, is a railway line in Northern Ireland, operated by Northern Ireland Railways. It runs as double track along the majority of its route north along the scenic east Antrim coastline from Belfast to the coastal seaport town of Larne, serving commuters and ferry passengers.

NI Railways, also known as Northern Ireland Railways, is the railway operator in Northern Ireland. NIR is a subsidiary of Translink, whose parent company is the Northern Ireland Transport Holding Company (NITHCo), and is one of eight publicly owned train operators in the United Kingdom, the others being Direct Rail Services, Northern Trains, Transport for Wales Rail, Southeastern, LNER, ScotRail, and TransPennine Express. It has a common Board of Management with the other two companies in the group, Ulsterbus and Metro.