Formal and informal employment have traditionally been perceived as separate. This division usually has a social, geographical and temporal character. However, it has also been argued that formal and informal economic practices are not necessarily distinctive and often coexist within the same spaces, firms or even jobs. This article explores the blurring boundaries between formal and informal work. By using examples from four sectors of the Irish economy, we demonstrate how some employers ‘informalise’ working conditions of their formal employees. As we show, such informalisation is mainly focused on cutting employment costs and setting earnings below the minimum wage. This has resulted in a further erosion of the formal–informal division in some sectors of Ireland's post‐recession labour market.