In this study, a parallel river transport scheme was developed to deliver runoff from the land surface to the oceans. Such a scheme is required in fully-coupled land-ocean-atmosphere models in order to close the global water cycle. Within each watershed, the river routing algorithm used cell-to-cell routing, in which a coupled system of ordinary differential equations was developed by considering the mass balance of surface inflows and outflows at each cell to or from adjacent cells. A Cray T3E computer was used for the development, using the MPI library for inter-processor communication to improve portability across computer platforms. Varying numbers of processors were used with the transport scheme to test the scalability of the algorithm. Validation tests of the transport scheme were conducted on a number of large river basins, and the sensitivity of simulated hydrographs to model resolution was explored by analysis of climate model runs of progressively higher resolution