<p>Persistent warm sea surface temperature (SST) biases in climate models are prevalent in eastern boundary upwelling systems, such as those in the Southeast Atlantic Ocean. Although these biases have been attributed to coastal wind forcing, the influence of mesoscale eddies remains unclear. This study addresses this gap using a regional oceanic modeling system driven by high-resolution weather research and forecasting (WRF) model outputs and the coarser coordinated ocean-ice reference experiments (CORE2) atmospheric forcing. We quantify the eddy distribution and its contribution to the heat convergence to assess its impact on the SST bias. Our findings reveal that mesoscale eddies in the Southeast Atlantic have horizontal scales of 50–300 km and extended vertical depths from 50 to over 400 m. They exhibit significant spatial and seasonal variability governed by distinct dynamics in the Angola-Benguela front, Benguela upwelling system, and Agulhas leakage regions. Across these areas, the mean flow generally cools the ocean, whereas mesoscale eddies provide a warming effect. A comparison of the WRF and CORE2-forced simulations demonstrates that the warm SST bias stems primarily from insufficient mean flow cooling, which is inadequately represented in the coarser models. In contrast, mesoscale eddies consistently counteract this cooling, acting as a buffer that mitigates rather than causes the development of the warm bias. These findings highlight that accurately resolving mean oceanic flows is essential to reducing SST biases in climate models.</p>