Air distance from Ulaanbaatar, Mongolia to Sydney, Australia is 6243.6 Miles (10048.2 Kilometers / 5422 Nautical Miles).
Flight duration time from Ulaanbaatar to Sydney is 12 hrs, 57 mins. 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.