Work Package 1 – Subpolar circulation, heat delivery and water mass export addresses the key processes, connectivity and circulation of the Antarctic shelf seas. An ambitious circumpolar programme of instrument deployments, including mooring and novel profiling float arrays over the continental shelf is proposed. This is supported by close partnerships with South Korean, New Zealand, Australian, German and Japanese collaborators. Combined with high resolution modelling and satellite observations, this will reduce the existing spatial and process gap in understanding. It will establish the role of Antarctic marginal seas in regulating heat delivery to the ice shelves (supporting WP2-4) and in the formation and export of dense water to the global ocean (supporting WP5-6).