Air distance from Hobart, Australia to Helena, USA is 8688.6 Miles (13982.9 Kilometers / 7545.2 Nautical Miles).
18 hrs, 2 mins is the flight duration between Hobart and Helena. This is the In-The-Air flight time. You should also add the taxi time, airport wait times and possible delays due to bad weather, etc. for the total flight duration time.