The airport closest to the city of Porto is located about 14 km to the north, in Maia. That's where my plane landed. At the Aeroporto Sa Cerneiro, as the airport is called in Portugese, you can find an ATM, a tourist information centre or a car hire. However, I decided to go straight to the underground.
I wanted to catch the last train to the centre of Porto.
The centre of Porto is about 35 minute drive from the Maia airport. The trains of the purple underground line run between 6.00 am - 12.30 am. I somehow managed to catch the last one which leaves the station thirty minutes after midnight. Thanks to that I arrived in the centre of Porto and at the Pilot hostel where I had booked a cheap accommodation.