The Benguela Air-Sea CO2 and Heat Flux Experiment was conducted on the Algoa Voyage 278 from 6 to 19 December 2021. The cruise operated on the West Coast of South Africa at a fixed location between Station 4 and 5 of the St. Helena Bay monitoring line (SHBML) with the ship's bow into the wind. The objectives of the cruise were to examine, using high-resolution Eddy Co-Variance (EcV) and in situ observations, the role of the ocean “cool skin” on the air-sea flux of CO2 and heat; to examine, through high-resolution observations, the impact of the vertical temperature gradient in the upper 10m of the water column on the estimation of the air-sea flux; to examine the sensitivity of 1 and 2 under a wide range of diurnal and synoptic wind stress and surface layer mixing conditions; to link the variability in the temperature gradients and pCO2 to mixed layer dynamics in response to the interaction of wind-linked mixing and heat-linked stratification; to understand the synoptic scale...