The data set includes sedimentological data (grain size distribution, facies compositions & radiocarbon ages) and satellite imagery data (shoreline analysis) of the reef island Langkai, SW Sulawesi, Indonesia. The data was collected in order to reconstruct the Holocene and modern (sediment) dynamics over the past ca 6,000 years. Sediment samples were obtained from sediment cores taken by percussion drilling and hand-held (Auger) coring in May 2016 and July 2021. Laboratory analysis of the sediments and shoreline analysis were carried out between 2021 and 2023. The grain size distribution was determined by dry-sieving of the bulk sample into fractions following Wentworth (1922). The subsequent analysis of grain size statistics was done in GRADISTAT v9.1 (Blott & Pye, 2001). The skeletal components of the grain size fractions >2 mm, 2-1 mm, 1-0.5 mm and 0.5-0.25 mm were analyzed under a digital microscope by point counting. A total of n=100 skeletal components were identified from each fraction. These results were then used to calculate the relative proportions in each sample. A total of 20 radiocarbon ages from AMS dating were calibrated using OxCal online v4.4 (Bronk Ramsey, 2009), with the MARINE20 curve (Heaton et al., 2020) and a regional reservoir correction of deltaR= 0+-0 as suggested by Southon et al. (2002). The shoreline analysis is based on satellite image data (1999-2023; acquired from multiple sources, see data set for detailed description) and was analyzed with the Digital Shoreline Analysis Tool (Thieler et al., 2009) in ArcGIS.