It is not as easy to get to Hokkaido as it is to get to a resort on the main island such as Hakuba. First you will need to get a flight to Tokyo’s Narita aiport (see here for flights) .After that you can either get a domestic flight or a train to Hokkaido.
By domestic flight
To get to Hokkaido you first need to get a plane to Tokyo’s Narita aiport (see here for flights) then get a domestic flight to Chitose international airport. Chitosei airport is the closest one to both Sapporo city and Niseko ski reosrt. If you are coming into Japan on an jetstar flight from Australia you will probably have to stay overnight at an airport hotel in Narita. See here for stay options. Both Jetstar and Skymark do cheap flights from Narita airport to Chitosei airport, with many departures a day (there are also many flights from Tokyo’s other airport, Haneda airport, but Haneda is at least an hour away from Narita and this is not much fun with luggage). Getting from Chitose airport to Niseko is very easy, there are shuttle buses running every half hour or so, taking about 3 hours and costing about ¥4,000 return. Here are a couple, but you generally will not be ble to book until the 1st October. •Hokkaido Resort Liner Skibus•White Liner bus.It is also possible to get a train but you will need to go via Sapporo (see here for timetables).
By Bullet Train & Bus
Many people will have a JR Train Pass which gives you unlimited train travel for 7,14 or 21 days. You need to purchase these BEFORE you arrive in Japan, once you get there it is too late. Since there is a tunnel running betweeen the main island of Honshuu and Hokkaido, it is easy to get the bullet train via Tokyo and Aomori to Sapporo (about 10 hrs). See this page for train timetables/costs. If you don’t have a JR pass then it will be cheaper just to get a flight. If you need to do an overnighter in Sapporo (one of the best cities in Japan) see this page for accommodation options. From Sapporo there are a couple of bus options such as the Hokkaido Resort Liner Skibus or the White Liner bus.You can also just train it via Otaru.