The RAPID-WATCH (Rapid Climate Change - Will the Atlantic Thermohaline Circulation Halt?) data set consists of pressure, current velocities, temperature, salinity and density time series. Measurements are collected by moored instruments deployed in arrays across the Atlantic at approximately 26.5N for the Monitoring the Atlantic Meridional Overturning Circulation at 26.5N (MOC) project and at each of three sections across the US and Canadian continental slope between Cape Cod and the Grand Banks for the Western Atlantic Variability Experiment (WAVE) project. The data set also consists of conductivity- temperature-depth (CTD) profiles, and ships' underway monitoring system meteorology and surface hydrography collected during the mooring deployment and servicing cruises. The RAPID-WATCH data set follows on from the original Rapid Climate Change (RAPID) Programme oceanographic dataset (2004-2008). It spans from 2008 until 2015. The RAPID-AMOC data set is expected to extend the RAPID_WATCH dataset to 2020. The main aims of the RAPID-WATCH Programme are to provide oceanographic measurements that allow a decade-long time series of the Atlantic Meridional Overturning Circulation to be derived for use in climate change research. The MOC project is led by scientists at the National Oceanography Centre in Southampton, whilst work on the WAVE element is led by the Liverpool site of the National Oceanography Centre.