Numerous field programs have been conducted with the intention of monitoring the transport variability of the Antarctic Circumpolar Current (ACC). Some programs are ongoing, with further efforts planned. Here we address, for the first time, the sampling frequency required for reliable monitoring of the ACC at interannual periods. We find that, for all practical purposes, sampling with a frequency significantly higher than weekly is required to obtain reliable annual means; coarser sampling leads to serious aliasing and degradation of the true temporal progression of transport. Monitoring changes in the seasonality of the ACC requires even more rapid sampling. In practice, hydrographic sections, repeat XBT sections and even altimetry along a single repeat groundtrack will fail to capture the true interannual variability; instead, in situ instrumentation (fixed gauges, moorings or bottom lander-based equipment) is required. Combinations of techniques may be useful, if they include data from fixed in situ sources.