Inclusion Criteria:

          -  Histologic demonstration of transitional cell carcinoma of the urothelium. Minor
             components ( less than [<] 50 percent [%] overall) of variant histology such as
             glandular or squamous differentiation, or evolution to more aggressive phenotypes such
             as sarcomatoid or micropapillary change are acceptable

          -  Metastatic or surgically unresectable urothelial cancer

          -  Documented progression of disease, defined as any progression that requires a change
             in treatment, prior to randomization

          -  Cohort 1: Prior treatment with an anti-PD-(L) 1 agent as monotherapy or as combination
             therapy; no more than 2 prior lines of systemic treatment. Cohort 2: No prior
             treatment with an anti-PD-(L) 1 agent; only 1 line of prior systemic treatment.
             Subjects who received neoadjuvant or adjuvant chemotherapy and showed disease
             progression within 12 months of the last dose are considered to have received systemic
             therapy in the metastatic setting.

          -  A woman of childbearing potential who is sexually active must have a negative
             pregnancy test (beta human chorionic gonadotropin [beta hCG]) at Screening (urine or
             serum)

          -  Participants must meet appropriate molecular eligibility criteria

          -  Eastern Cooperative Oncology Group (ECOG) performance status Grade 0, 1, or 2

          -  Adequate bone marrow, liver, and renal function

        Exclusion Criteria:

          -  Treatment with any other investigational agent or participation in another clinical
             study with therapeutic intent within 30 days prior to randomization

          -  Active malignancies (that is, requiring treatment change in the last 24 months). The
             only allowed exceptions are: urothelial cancer, skin cancer treated within the last 24
             months that is considered completely cured, localized prostate cancer with a gleason
             score of 6 (treated within the last 24 months or untreated and under surveillance) and
             localized prostate cancer with a gleason score of 3+4 that has been treated more than
             6 months prior to full study screening and considered to have a very low risk of
             recurrence.

          -  Symptomatic central nervous system metastases

          -  Received prior fibroblast growth factor receptor (FGFR) inhibitor treatment

          -  Known allergies, hypersensitivity, or intolerance to erdafitinib or its excipients

          -  Current central serous retinopathy (CSR) or retinal pigment epithelial detachment of
             any grade.

          -  History of uncontrolled cardiovascular disease

          -  Impaired wound healing capacity defined as skin/decubitus ulcers, chronic leg ulcers,
             known gastric ulcers, or unhealed incisions