In the United Kingdom and internationally, synthetic cannabinoids (SCs) are a common adulterant in illicitly sourced vaping products. Recently, their use is increasingly being linked to severe health effects, particularly among children. Here, we aimed to conduct the first detection and quantification of SCs in illicit disposable vaping products. A cross-section of seven illicitly sourced disposable vape samples that were initially sold as cannabis products was submitted for analysis by a single individual presenting to a drug and alcohol service in the United Kingdom. Qualitative and quantitative analyses of these samples were conducted using nuclear magnetic resonance and gas chromatography/electron ionization-mass spectrometry. Qualitative analysis identified the SC 5F-MDMB-PICA in all seven samples, in the absence of any other pharmacologically active compounds. Quantitative analysis revealed that the median concentration of 5F-MDMB-PICA was 0.85 mg/ml (range = 0.59-1.63). The external appearance of these vape samples closely resembled regulated vaping products, and the presence of SCs was not identifiable by any labelling or packaging. The SC 5F-MDMB-PICA was detected at a median concentration of 0.85 mg/ml in seven disposable vapes which were illegally sourced in the United Kingdom, were mis-sold as cannabis products and closely resembled legal, regulated products.