The fifth-generation (5G) ultra-dense cellular networks may face redundant handover problems due to the small coverage areas of small cells and the mobility of users, which leads to significant packet losses and network delays. Therefore, the overall user experience may degrade. In this paper, we propose a user clustering-based handover mitigation algorithm to improve the user experience for fast-moving users. To that end, the algorithm detects fast-moving users and finds their locations. Therefore, fast-moving user groups are formed by applying a clustering technique, where a central user becomes a small cell to serve the remaining users in each cluster. Simulation results demonstrate that the approach can mitigate 96.76% redundant handovers and maintain an average network throughput of 100 Mbps.