Stormwater is recognised as a vector for microplastics (MPs), including tyre wear particles (TWPs) from land-based sources to receivingwaterbodies. Before reaching the waterbodies, the stormwater may be treated. In this study, sediments from six treatment facilities (fiveretention ponds and a subsurface sedimentation tank) were analysed to understand MP occurrence, concentrations, sizes, polymer typesand distribution between inlet and outlet. The concentrations of MPs showed large variations between and within different facilities withMP concentrations of 1,440–72,209 items/kg (analysed by μFTIR) corresponding to 120–2,950 μg/kg and TWP concentrations from ,DL upto 69,300 μg/kg (analysed by pyrolysis–GC–MS), with significantly higher concentrations at the inlet compared to the outlet. Polypropylene(PP) was the predominant MP type in terms of number in all samples. TWPs were dominant by mass in most (nine) samples. The relativelylow density of PP polymers implies that density might not be the sole factor influencing particle settlement behaviour. Small particlesoccurred more frequently than large ones; around 70% of the particles detected in the samples were 100 μm or smaller. In summary, thisstudy highlights the occurrence of MPs, including TWPs, in stormwater facilities and demonstrates variations in concentrations dependingon sites and locations within the facility.