ABSTRACT Unsupervised technology use by children is increasing rapidly and with it, a common area of crime is emerging: Technology Assisted-Harmful Sexual Behaviour (TA-HSB). Previous research has demonstrated that there are significant differences between adult offenders displaying TA-HSB, offline Harmful Sexual Behaviour (offline HSB) and those displaying both (dual HSB). This study aimed to investigate these differences further within a community adolescent forensic population over a period of four years (1 April 2018 to 31 March 2022). The demographic characteristics and TA-HSB typologies of an adolescent forensic population who were displaying TA-HSB (n = 43), offline HSB (n = 116) and dual HSB (n = 130) were examined. The implications for future research are discussed. PRACTICE IMPACT STATEMENT This evaluation promotes a greater sense of awareness and knowledge of the characteristics of young people engaging in TA-HSB in a community adolescent forensic service and the incidence and types of TA-HSB they engage in. Findings help develop an understanding of risk formulation, differential needs and support of young people presenting with TA-HSB.