Maybe not all roads lead to Gdansk, but it is possible to reach the city from the land, air, and water.
The fastest way is the airplane. Direct flights are from 60 European cities and Tel Aviv. On the Lech Walesa Airport operate KLM, SAS, LOT, Lufthansa, Norwegian, Finnair, and cheap airlines Ryanair, Wizzair and Baltic Air. In 2018 there were about 5 million passengers that used these services.
The airport is well connected for transportation with the city. Available there is the train SKM (Szybka Kolej Miejska - Fast City Railway). A trip from the airport to the center of the city takes about 40 minutes. There are also a plenty of bus lines both in the day and one in the night.
Taxi services from the airport to the Old City should cost from 40 to 70 Zlotys. It depends on the taxi company and the arrival time. It is much more expensive on Saturday, Sunday, public holidays and during the night. Booking of the taxi via mobile applications may result in not only a scheduled taxi at a particular time, but, even lower costs. Services like uber or iTaxi are available, however this may vary.
The main station (Dworzec Główny) is very close to the Old City. The walk from the train station to the city takes about 10-15 minutes. The same train usually runs not only to Gdansk but also to Sopot and Gdynia.
Tourists traveling from Sweden or Finland are able to use a ferry. There is a ferry from Nynashamn (close to Stockholm), which runs directly to Gdansk. The trip takes 19 hours, and cost is about 400 zlotys.
The ferry from Karlskrona runs to Gdynia. Same as a ferry from Hanko (Finland). There was also the ferry from Helsinki, but it is suspended now