The DESY campus is located in Bahrenfeld, in the west of Hamburg. The address is Notkestraße 85, 22607 Hamburg. It is well reachable by public transport. The campus is open to the public but access by car requires a permit.
Access from the airport by public transportation:
Take the train S1 in the direction Wedel or Blankenese from Hamburg Airport (Flughafen) to Othmarchen (18 stations). In Othmarchen, take the east exit and turn right at the end of the stairwell. You will see a small place with Jim Block and several bus stations. Take the bus number 1 in the direction of Rissen or Schenefelder Holt. Exit at Zum Hünengrab (5 stops).
See here to plan your trip by bus. Price of a trip is 3.30 euros (Hamburg AB / Großbereich). Travelling time is about 1 hour.
Access from the airport by taxi:
A taxi can be taken from the airport to DESY. A trip cost around 40 euros. The travelling time is around 30 mins depending on the traffic.
Further travel details can be found here.