O21｜Tainan Bus

Navigation｜O21 Real-Time Arrival、O21 Timetable、O21 Route Map
Bus with Same Name｜NewTaipei O21 Bus、Kaohsiung O21 Bus

Navigation｜O21 Real-Time Arrival、O21 Timetable、O21 Route Map

Others｜O3 Bus、O4 Bus、O4-1 Bus、O5 Bus、O6 Bus、O9 Bus、O9-1 Bus、Orange Bus、R1 Bus、R10 Bus、R11 Bus、R12 Bus、R13 Bus、R14 Bus