Per- and- polyfluoroalkyl substances (PFASs) are widely used in commercial and industrial products and leach into the environment from different applications. PFASs poses an issue to both wildlife and humans because of different toxic properties. Different PFASs have been found to effect different hormones, are possibly carcinogenic, or can affect metabolic function. Many initiatives have been started by countries, organisations, and companies to prevent PFASs from ending up in the environment. Aquatic environments are a sink for PFASs, and much research has been done on the marine environment and its residents to investigate the effects of these substances. In earlier research, the need for a time-line perspective combined with both a total fluorine analysis and mass spectrometry analysis has been pointed out. This study's objective was to investigate how the concentrations of known and unknown bioaccumulating organic fluorinated substances in pilot whales are evolving over time. The results show fluctuating levels of PFASs for the different whales, making it hard to view any trends. There is a pattern of the unknown organic fluorine, that is increasing after 2009 when the phase-out of perfluorooctane sulfonate (PFOS) happened. The highest amount of unknown fluorine is 77% in one of the samples. Short-chain PFASs seems to be a good short-term solution as a replacement for the long-chain PFASs but could pose a threat over a longer time perspective. Both pilot whales and humans risk getting high concentrations of PFASs through biomagnification, the acceptable daily intake (ADI) that are in place regarding PFASs should possibly be on total organic fluorine (TOF) instead, due to the high percentage of unknown organic fluorine.