The seas of the Maritime Continent feature a unique combination of processes that present a challenge to both our observational and modelling capabilities. Supporting one of key interbasin connections in the global overturning circulation, it is also the site of strong water mass conversion due to the action of tidally-driven mixing, is located between the two largest warm pools on the planet where atmospheric deep convection occurs and is subject to incoming planetary wave energy from both the Indian and Pacific Oceans. Since the comprehensive INSTANT campaign in 2004-2006, moored and ship-based studies have shed further light on the dynamics and changes in this region, along with great progress in modelling studies targeting tidal through to multidecadal processes. Here we will review this progress and also lay out the remaining knowledge gaps and challenges we face in building a more comprehensive understanding of the role of the seas in the Maritime Continent on weather and climate.  A new international field program targeting some of the challenges will be described.