We investigated plankton samples collected during RV Polarstern cruise ANT-XXVI/2 (from 27th November 2009 to 27th January 2010) along a broad E-W transect in the Pacific sector of the SO during austral summer. One hundred and fifty samples from twenty-nine stations were collected from the upper 150 m of the water column. Coccospheres per liter were counted using a scanning electronmicroscope (SEM). The different extant coccolithophore taxa numbers and assemblage distribution in relation to the frontal dynamics of the SO provide valuable information for potential future paleoceanographic reconstructions.