Variations are inevitable in any construction project. People tend to view variations as a natural and inherent part of construction work, due to the complexity of the construction project. Lack of knowledge, inexperience, and wrong expectations frequently caused variations and eventually lead to exceeding the project cost. Hence, minimising variations in construction projects is vital to the sustainable delivery of the project. Poka-Yoke is a Japanese mistake-proofing method that received wider recognition in the service industry. However, there is a lack of research on how Poka-Yoke can be implemented to minimise mistakes in construction projects. Therefore, this research is aimed to investigate the benefits and barriers of Poka-Yoke implementation for Sri Lankan construction projects to minimise variations. To collect qualitative data, semi-structured interviews were conducted with experts, and code-based content analysis through NVivo 12 was used to analyse the data. As Poka-Yoke is novel to the Sri Lankan construction industry, the identified nine barriers will pave the way for professionals to avoid the existing barriers by taking necessary precautions prior to implementation. Thus, the findings further emphasised the need for the government to provide proper knowledge through training sessions. The identified fifteen benefits will be encouraged professionals to use Poka-Yoke to minimise the causes of variations in construction projects. The construction industry professionals, Engineers, Architects, and Quantity Surveyors have to bind their greatest involvement during the designing stages to minimize the variations and thus benefit from the research findings.