This dataset supports a high-resolution paleoceanographic reconstruction of Antarctic Intermediate Water (AAIW) transport and Intermediate Western Boundary Current (IWBC) variability over the past 16,300 years based on sediment core SANBIF-777, retrieved from the southeastern Brazilian continental margin (1136 m depth). The data include sortable silt percentages, mean sortable silt grain size, end-members, and age-depth information derived from calibrated radiocarbon dates. Grain size distributions were measured at 1 cm resolution and used to infer changes in bottom current strength associated with the IWBC, which transports AAIW northward. These measurements provide insights into the response of intermediate water circulation to abrupt climate events such as the Younger Dryas and Bølling-Allerød. These data contribute to a better understanding of past intermediate-depth circulation and its role in millennial-scale climate variability.