The research aimed to present a unique 'snapshot' of legal psychoactive drug use prior to legislative control in Ireland, in relation to the types of products used; sourcings; consumptive practices and particular social settings for use; gauging of dosage; licit and illicit drug transitions, individualisation of drug decision-making and experiences; and future intentions regarding drug switching post legislation. Semi-structured in depth interviews (n = 32) were conducted with adults aged 18-33 years who had used legal highs in the 6 months prior to fieldwork. The findings indicate some support for 'differentiated' displacement consumptive patterns between illegal and legal drugs, with user pathways grounded in 'legal high' availability; perceived user effect, safety, legality, quality and price. Mephedrone emerged as most popular drug of choice. Internet sales, stockpiling and diversion of previously 'legal highs' onto the illegal street drug market remain of concern, against a background of emerging new designer drugs in Ireland.