The closest airport to Tainan is the Tainan Airport (TNN). However, international travelers are more likely to arrive at Taoyuan International Airport (TPE) in Taipei or Kaohsiung International Airport (KHH).
From Taoyuan International Airport, you can take the High-Speed Rail (HSR) from Taoyuan HSR station to Tainan HSR station. The journey takes approximately 2 hours.
From Kaohsiung International Airport, you can take a taxi or the KRT to Kaohsiung Main Station, then switch to a local train or HSR to Tainan, which takes about 30 to 45 minutes.
If you are already in Taiwan, taking the HSR to Tainan is a convenient option. The HSR connects major cities across the country. The ride from Taipei to Tainan takes approximately 90 minutes.
The regular Taiwan Railways (TRA) is another alternative. From the main cities, take a train bound for Tainan Station, located in the city center. Travel times will be longer than the HSR, but it's a more scenic route that allows you to see more of the countryside.
Long-distance buses connect various Taiwanese cities to Tainan. These can be cheaper, but also slower, compared to the HSR or TRA trains. Buses to Tainan can be boarded at Taipei, Kaohsiung, and other major bus terminals.