This dataset presents the concentrations of chemical contaminants of emerging concern (CECs) in common dolphins (Delphinus delphis) from the Bay of Biscay (NE Atlantic). Tissue samples of liver and blubber were collected on a total of 61 individuals between 2000 and 2023. These individuals encompass 51 stranded animals recovered by local stranding networks and 9 bycaught individuals directly observed on board (dead animals). The targeted CECs included: i) the halogenated norbornenes (or dechloranes, DECs), ii) the alternative brominated flame retardants DBE-DBCH (α and β isomers), PBEB, BEH-TEBP, BTBPE, iii) polyhalogenated carbazoles (PHCZs), iv) the personal care products triclosan (TCS) and its metabolite methyl-triclosan (Me-TCS), v) bromophenols (BPs), vi) per- and polyfluoroalkyl substances (PFAS) including C₄ to C₁₂ perfluoroalkane sulfonates (PFSAs) and C₅ to C₁₄ perfluoroalkyl carboxylates (PFCAs), and vii) Rare Earth Elements (REEs - 14 elements). CEC concentrations were measured in liver (PFAS and REEs) or blubber (other CECs).