Sopot is part of the Trójmiasto (Tri-City) conurbation and is well-connected to Gdańsk and Gdynia by the SKM commuter rail. The journey from Gdańsk Główny (main station) takes about 20 minutes with frequent departures throughout the day; from Gdynia it's about 15 minutes. The SKM is cheap and reliable — buy tickets at machines on the platform.
The nearest airport is Gdańsk Lech Wałęsa Airport (GDN), about 20 km from Sopot. Trains from the airport require a change at Gdańsk Główny. Taxis and ride-share services are available directly from the airport.
By car, Sopot is on the S6 expressway and is connected to Gdańsk via the A1 motorway junction. Parking is limited and expensive in summer; arriving by train is strongly recommended for day trips or if you're based in Gdańsk.