The Indonesian Directorate General of Immigration launched an online passport service application in early 2019 to make people queue for passport documents more efficiently and quickly. After being available in Google Play and App Store, several issues appeared on its user interface by distributing an online questionnaire to identify User Interface/User Experience (UI) problems with this application. The preliminary evaluation results indicated that the existing online passport service application designs received below-average results, indicating that the current design should be improved. This research performed the User-Centered Design technique to design and develop the improved UI/UX design by analyzing user needs. The results of the UEQ method evaluation for new designs revealed that the overall average value has increased. This research generated a new UI/UX design where these dimensions' scores were increased: Attractiveness (-0.24 to 1.63), Perspicuity (0.27 to 1.63), Efficiency (-0.18 to 1.75), Dependability (-0.30 to 1.75), Stimulation (0.11 to 1.77), and Novelty (-0.59 to 1.45). Therefore, this research solved the UI/UX issues to enable user satisfaction and meaningful experience by implementing the User-Centered Design approach.