Seasonal variations in the speed of the Earth's rotation manifest themselves as fluctuations in the length of the day (LOD) with an amplitude of about 1000 microseconds (&mgr;s). We know from previous work that at least 95% of these variations can be accounted for in terms of angular momentum exchange between the atmosphere and the solid Earth. Here we examine the respective contributions of the Antarctic Circumpolar Current (ACC) and the global oceans to the Earth's seasonal angular momentum budget, using in situ data from the Drake Passage and results from both the oceanic regional model (Fine Resolution Antarctic Model-FRAM) of Webb et al. [1991> and the global oceanic model of Maier-Reimer et al. [1993> as analyzed by Brosche et al. [1990>. The estimated annual contribution of the ACC (2--4 &mgr;s) is much smaller than the total variation in the oceanic models or existing LOD-AAM residual (both ~15--20 &mgr;s). The estimated semi-annual ACC contribution (3--8 &mgr;s) is offset by counter-currents further north in both oceanic models, which exhibit larger semic-annual variations in planetary angular momentum. Further refinements in the Earth's seasonal angular momentum budget, therefore, will require the full (planetary plus relative) contribution of the global oceans in addition to that of the ACC.