We performed geochemical, sedimentological and micropaleontological analyses on a 9.2 m long radiocarbon-dated sediment core collected from Larenas Bay (48°S; Chile) to reconstruct basin isolation and marine ingression over the last 16.8 kyr. The LAR sediment core was collected with a 5 m long Uwitec piston corer (63 mm diameter) onboard the R/V Gran Campo II on September 12th 2008. Two overlapping ~4.6 m long piston cores (LAR I and LAR II) and a 65 cm long gravity core that preserved the sediment-water interface were retrieved. To investigate modern sediments, the top centimeter of an additional Rumohr gravity core (LAR R2) taken at the same location on January 19th 2020 was used. The piston cores were sampled in 2 cm thick slices which were subsequently freeze-dried. Discrete analyses were performed at a 10 to 20 cm interval. A separate set of 1 cm thick samples was used for density measurements.