Kaohsiung, Tainan or Chiayi via the South-Link Line to Taitung, then Route 201 to Fugang Ferry Pier and a sailing to Green Island — the most direct approach from the south.
From southern Taiwan, Green Island is the most direct of the offshore-island runs — just take TRA along the South-Link Line straight into Taitung. EMU3000 Tze-Chiang Limited Express or Puyuma Express from Kaohsiung clocks about 1 hr 47 min at the fastest, slower services about 2 hours. From Tainan or Chiayi, connect at Kaohsiung, or board a reserved-seat service that already passes through Kaohsiung.
From Taitung Train Station, board Puyuma Transport Route 201 at Bay 1 to Fugang Ferry Pier (about 20 minutes, NT$25), then take the ferry across to Nanliao Harbor on Green Island (about 50 minutes) — the Green Island line is operated in rotation by three companies: Kaixuan, Tianwangxing, and Lyudao Star.
The Green Island route runs 2 fixed sailings on weekdays (09:30 and 13:30); in high season and on weekends and holidays it scales to 5 sailings a day (07:30 / 09:30 / 11:30 / 13:30 / 15:30).
You have far more flexibility on sailings than travelers from the north. A 05:00–06:00 train out of Kaohsiung gets you to Taitung around 07:00–08:00, perfectly timed for the 08:10 or 08:30 bus to Fugang and the 09:30 weekday first sailing. To catch the high-season 07:30 extra you would have to leave Kaohsiung in the middle of the night for the 06:20 bus — most people prefer to overnight in Taitung instead.
The South-Link Line passes Jinlun and Taimali, where mountains meet the sea — well worth looking up from your phone for the view. Duoliang Station is on the line, but trains have not stopped there since 2006; reach the Duoliang viewpoint by car or bus. The South-Link Line is often suspended during typhoon season (July–November), and both 2024 and 2025 saw several major shutdowns, so always check the TRA advisory before you leave. For ferry tickets and current capacity, ferry.tw is the authoritative source.