This study explores the relationship between dinoflagellate cyst (dinocyst) assemblages and the mixed layer depth (MLD) using canonical correspondence analyses. Our results demonstrate that wintertime deepening of MLD, in response to deep convection events, can influence dinocyst assemblages and especially the relative abundance of Nematosphaeropsis labyrinthus, which can thus be used as a proxy of MLD and the associated deep convection intensity. The analysis of Holocene N. labyrinthus percentage records in the subpolar North Atlantic, along with quantitative reconstructions of MLD from dinocyst assemblages, further reveals a westward migration of potential deep convection region around 6 ka BP, from the Nordic Seas and eastern subpolar gyre (SPG) during the Early Holocene, to the western to central SPG during the Middle and Late Holocene. The intensification of deep convection in the Labrador Sea towards a modern-like situation started during the Late Holocene, one or two thousand years later than the major transition around 6 ka BP in other parts of the subpolar North Atlantic. These results strengthen the hypothesis of reduced deep-water formation in the eastern North Atlantic from the Early to Late Holocene.