Sea ice plays a major role in governing the exchange of energy and moisture between the ocean and atmosphere in the polar regions. Changes in the thickness and extent of the Antarctic sea ice may be harbingers of climate change; however, results from global climate models indicate that there is still much to be learned about the details of the complex atmosphere–ice–ocean interaction. To improve our understanding of this system, access to field measurements is crucial for the development of parameterizations of sea-ice thermodynamic and dynamic processes. Near-coastal fast ice provides a reliable platform to access the sea ice over repeated years and at high temporal frequency. A prototype integrated observing system, the Antarctic Fast-Ice Network (AFIN), has been developed for in situ measurements of the vertical fast-ice mass balance, of the horizontal fast-ice extent as well as of environmental data. Instrumentation includes ice thermistors, snow-thickness pingers, sensors for air temperature, pressure and wind data, and underwater temperature sensors. In addition, coincident satellite-derived data are obtained to assess the regional evolution of the fast ice, especially with a view to tracking changes of the surrounding pack ice. To improve our knowledge of how the ice algal biomass is coupled to physical sea-ice properties and local oceanographic and atmospheric conditions, our current planning is towards the integration of in situ measurements of ice algal biomass and suspended chlorophyll into the AFIN. At the same time, it is crucial to expand the spatial sampling mask. It will be possible to detect large-scale variability in the fast-ice response to changes in the current climate system, by obtaining data from locations spread around much of the Antarctic coast. Several international collaborators have already signed up to conduct or support AFIN measurements from their coastal stations. Sustained and consistent observations of the Antarctic fast-ice system are pivotal to address key questions, such as: (1) Is Antarctic sea-(fast-)ice thickness changing, and, if so, what is the spatio-temporal variability of these changes? (2) How are changes in Antarctic ice thickness linked to the changes observed in the surrounding ocean and atmosphere? (3) How is ice algal biomass coupled to physical sea-ice properties and local oceanographic and atmospheric conditions? (4) How does the fast-ice extent respond to changed atmospheric (and oceanographic) conditions? Here we will present first results from an Antarctic fast-ice mass-balance site and provide an outlook on the AFIN system.