How to get in to Taipei city from Taoyuan International Airport (TPE)
Since 2017, the best way to get in to the city from Taoyuan airport is by train with the Airport MRT.
As of 2019 the train departs from terminal 1 and 2 (terminal 3 will be connected in the future), and gets you to Taipei Main Station, right in the heart of the city and the main transportation hub where you can connect to metro, intercity buses, trains, and even high speed trains
There are two kinds of trains - express and commuter. Take express if you can. Fare is the same and they both run along the same route but commuter train makes more stops along the way. Trip to Taipei Main Station takes 36 minutes on express and 50 minutes on commuter. First train to the city is at 5:59, last train to the city is at 23:36
Fare is 160 NT each way, or $5.2 USD. You can pay by cash or EasyCard. Credit card is not accepted for payment or purchase of EasyCard. I highly recommend getting EasyCard because you can use it for pretty much all your transportation needs in Taipei
This airport MRT train also goes in the opposite direction away from Taipei, so make sure you get on the right direction.
You can also take this train to get to Taoyuan High Speed Railway Station, which is the closest high speed train station to the airport. If you need to connect to high speed train this is the station you should use instead of going to Taipei. To get to Taoyuan HSR Station you need to take the MRT train going in the opposite direction from Taipei (away from Taipei)
The other public transport option is to take a bus:
There's a pretty comfortable bus that runs from the airport to the main bus station (literally called Taipei Main Station), which is located right next to the main train station (Taipei Station). This station is a very good spot to get to other parts of the city by subway or taxi
Route: either route #1819 or #1961 can get you to the main station, but they stop at different stops along the way. I took bus #1819 because it was faster than #1961
#1819 took about 60 minutes, costs 140 TWD (~USD$5)
#1819 departs from both terminal 1 and terminal 2, just follow the signs for ground transportation when you exit the baggage claim area
You need to buy the ticket at the booth before you board the bus. Just go up to the booth and tell them you're going to the Taipei Main Station (台北車站) . They'll give you the right ticket