ABSTRACTAt archaeological sites located on islands or near the coast, the potential exists for lipid extracts of potsherds to contain fatty acids (FA) from both aquatic and terrestrial organisms, meaning that consideration must be given to marine reservoir effects (MRE) in radiocarbon (¹⁴C) analyses. Here we studied the site of Bornais (Outer Hebrides, UK) where a local MRE, ΔR of –65 ± 45 yr was determined through the paired ¹⁴C determinations of terrestrial and marine faunal bones. Lipid analysis of 49 potsherds, revealed aquatic biomarkers in 45% of the vessels, and δ¹³C values of C_16:0 and C_18:0 FAs revealed ruminant and marine product mixing for 71% of the vessels. Compound-specific ¹⁴C analysis (CSRA) of FAs yielded intermediate ¹⁴C ages between those of terrestrial and marine bones from the same contexts, confirming an MRE existed. A database containing δ¹³C values for FAs from reference terrestrial and marine organisms provided endmembers for calculating the percentage marine-derived C (%_marine) in FAs. We show that lipid ¹⁴C dates can be corrected using determined %_marine and ΔR values, such that pottery vessels from coastal locations can be ¹⁴C dated by CSRA of FAs.