For those NOT already in Australia

Air New Zealand - Is flying direct to Brisbane from all main centres in NZ. From Brisbane airport you can catch a Connexions bus (see below) from the airport to the Sunshine Coast door to door. If there are two or more of you; and you aren't getting a car, I would suggest looking at a private Uber as it would most likely be cheaper.

Jetstar - Seems to have direct flights to Sunshine Coast on Tuesdays, Fridays and Sundays.

Con-X-ion Bus - Door 2 Door Shuttle. From Brisbane to Sunshine Coast & Return is approx. $150 (single)-$238 (Couple) - www.con-x-ion.com

Car Hire - All the usual suspects are available. Apparently https://www.eastcoastcarrentals.com.au/ is quite good.