bˈeɪ fˈɪftiəθ stɹˈiːt ˈoʊpənd ˌɔn dʒuːlˈaɪ twˈɛnti wˈʌn, nˈaɪntiːnhˈʌndɹɪd sˈɛvəntˌiːn æz pˈɑːɹt ʌvðə fˈaɪnəl ɛkstˈɛnʃən ʌvðə bˌiːˌɛmtˈiː wˈɛst ˈɛnd lˈaɪn fɹʌm twˈɛnti fˈɪfθ ˈævənˌuː tə kənˈaɪ ˈaɪlənd.
Bay 50th Street opened on July 21, 1917 as part of the final extension of the BMT West End Line from 25th Avenue to Coney Island.