When a construction project commences, one of the primary objectives is to finish within the prescribed timeframe agreed between the contractor and client. However, it is increasingly common for construction projects to be delayed, particularly in the context of larger developments, primarily due to their increased complexity. This study aims to identify how variations impact the programme of a construction project. In doing so, a manufacturing facility in a pharmaceutical plant in the west of Ireland is selected as a case study. This study examines all variations that occurred and examines whether the variations are client, contractor, or other stakeholder-initiated. A detailed literature review was provided, where a critique of the literature resulted in 14 potential variations being identified. To complement this and to identify variations specific to the case study in question, a series of semi-structured interviews with industry professionals on the respective case study are undertaken. In total, 161 variations were identified and grouped based on the origins: client, contractor, or other. The variation register obtained from the main contractor was the primary data source for this research paper. To ensure comparability, results were analysed consistently, linking key phrases and topics from each research method undertaken. This study’s key findings were that variations negatively affected the project programme and, in this instance, extending 5 months to a 12-month contract. Furthermore, it was discovered that client-led variations have the largest impact on the project programme, with 93% of variations being client-initiated. This paper illustrates the importance of tracking variations that may be contractor/client-initiated. Further research is required across a broader range of projects to accurately determine the negative effect of variations on the project programme.