Real-world data on health-related quality of life (HRQoL) in advanced urothelial carcinoma (aUC) receiving immune checkpoint inhibitors (ICIs) are limited. This study included 42 patients with aUC who received second-line or later pembrolizumab (n = 19), maintenance avelumab followed by first-line chemotherapy (n = 13), or adjuvant nivolumab after radical surgery (n = 10). Time-course changes in the domains and scales related to HRQoL were evaluated using the EORTC QLQ-C30, FACT-G, and SF-8 questionnaires during ICI therapy. Anchor-based approaches for minimally important differences were determined as ‘improved’, ‘stable’, and ‘deteriorated’. We found significant improvements after the start of pembrolizumab treatment on many scales. Almost none of the scales changed significantly in the avelumab and nivolumab groups. Approximately 80% of the pembrolizumab group had deteriorated social/family well-being in FACT-G. Approximately 60% of the patients in the avelumab group had deteriorated general health and vitality in SF-8. In the nivolumab group, none of the scales deteriorated in > 50% of the patients. Deterioration of physical function in the SF-8 was associated with occurrence of treatment-related adverse events ≥ grade 2 during ICI therapy (P = 0.013). Our findings demonstrated that majority of patients with aUC who received ICI therapy had a stable HRQoL, which was consistent with evidence from clinical trials.