The longitudinal Belfast Youth Development Study (BYDS) followed a group of young people from age 11 to 21 years (from 2001 to 2011), charting their experiences of substance use, offending, education, and peer and family relationships. This allowed the investigation of risk and protective factors associated with different types of behavioural patterns and outcomes in adolescence and emerging adulthood. A feasibility study was carried out from 2018 to 2019 to test the success rate of electronically tracing 4,195 participants after almost a decade, in anticipation of carrying out an additional wave of data collection. The projected trace rate obtained using standard and forensic electronic tracing methods was considerably higher (86%) than traditional tracing methods (10%) for getting up-to-date contact details on participants. The electronic tracing methods were also cheaper (£9.72 per person traced) than traditional tracing methods (£20.62 per person traced). These findings will help maximise the potential of longitudinal social research.