This article explores union responses to subcontracting in the context of the Irish telecommunications sector. Through a longitudinal case study the development of strategy is traced over a number of years as the union moved away from a policy of exclusion towards one of engagement. As the findings show, a three-tiered approach brought successes in terms of the retention and recruitment of workers on non-standard contracts. Yet this brought tensions over the role of the union in the regulation of the subcontracting process. © The Author(s), 2009.