Background. A service encounter is the moment that a client directly interacts with a service firm. It is a social-oriented activity that an in-depth analysis of how the client behaved can contribute to the service quality. Objective. The primary objective of this study was to cluster the CLT into groups. The secondary objective was to discover the sequence of question types that asked in each group. Method. A real world call centre outsourcing practice and data mining techniques are used to discover client behaviour. Results. A total of 100,703 inbound calls from the call centre operational database are analyzed. 90.4% of the total calls were made by 85% of clients who used up to three business applications. 72.03% of the total calls were made by a group of clients who involved two to five question types. The clients were clustered into four groups by three behaviour variables. The sequences discovered in this study were mainly on two question types. Conclusion. The service encounter is a complex business process that an integrated perspective should be taken to analyze the dynamics among the entities involved. The client behaviour can be discovered and used as the feedback information for turning the operations in different organizational levels.