Chinggis Khaan international Airport is the main entrance point into the country. if you have obtained a visa for more than 30 days you will need to register with immigration which is in a building next to the Nadaam stadium which is walking distance from the airport (walk to the road and turn right out of the airport, the Nadaam stadium is a large red building, you can’t miss it) this is very important as if you are late with registration you will be fined up to £500, and make sure you ask if you need to deregister before you leave. from the airport you can take a taxi to Ulaanbaatar city centre which should cost max T15000, do not used a taxi with a meter as you will more than likely get ripped off, agree a price before getting into the taxi. however, it is easy to catch a bus, and much cheaper (the bus stop is outside the airport and turn right onto the main road, on the same side of the road as the airport) the number 22 will take you to peace avenue, past the state department store, and the number 11 will take you past Sukbataar square. All buses have a flat fare of T300 but may be crowded. Although there are no time tables you will never wait more than 20 minutes for a bus.
You may also arrive via train, a tip here is to buy your ticket to the nearest border town and cross the border on foot, after which catch a train to Ulaanbaatar, it makes it a lot cheaper. Train travel is cheap but usually long journeys and restricted destinations, buy your ticket in advance as prices rise when you buy on the train, for most journeys there are 3 classes, 1st class which is a 2 person sleeper cabin, 2nd class which is a 4 person sleeper cabin, and 3rd class which is seating. 3rd class is obviously the cheapest and the seats can be made into beds and bags can be put underneath them, as long as you don’t mind lack of privacy and possible crowds. The door areas in the trains (between carriages) are smoking areas.