Alotau

By plane
By plane

Alotau's airport is called Gurney, named after a WW2 fighter pilot.

Air Niugini
has daily flights from the nation's capital, Port Moresby. (http://www.airniugini.com.pg/)
Airlines PNG
has daily flights from Lae as well as Port Moresby and also connects Alotau twice-weekly with the Trobriand Islands and with Misima. (http://www.apng.com/)
By ship
By coastal freighter.

It may be possible to reach Alotau from Port Moresby or Lae by cargo freighter. There is no passenger-only shipping. Ask around at Port Moresby or Lae harbors, and be prepared for a long wait!