Mussels were sampled on seven monitoring stations in areas used as bivalve molluscs (Mytilus galloprovincialis) production in La Spezia Gulf (Italy) during 2019-2023. In the Portovenere Bay there are 2 zones named as PORT1 and PALM3; meanwhile in the outer dam there are 5 zones named DFPI5 DFCI6, DFLI7, DFLE8 and DFPE9. For each monitoring station, mussels were collected grouped in different points and, moreover, at three levels of depth (on the bottom, in the centre and at 50 cm from the surface), to obtain an aliquot of about 2–3 kg for each point. For the chemical analysis, the sampling rate is six-monthly during all the year. During all the period investigated PAHs concentration was monitored. In particular, the chemical analysis was focused on the detection of the Benzo[a]pyrene, Chrysene, Benz[a]anthracene and Benzo[b]fluoranthene, hereinafter BaP, ChR, BaA and BbF. Data are here presented as averages by years.