Train and bus connections to Olsztyn are available from most major cities in Poland.
For more information please refer to:
http://www.pks.olsztyn.pl — PKS Buses
https://en.e-podroznik.pl/ – PKP Trains
Town buses & trams
If you want to move around the town use this site in order to check which bus/tram you should take. (this app is available in Polish by default. In order to change the site’s language to English tap settings icon in the upper corner. Then change “Wybierz język” property to “Angielski” in the popup that appears)