You can also take the bus from Santiago, Chile with departures from 08:30 AM-1:30 PM to Mendoza from the "Los Heroes" bus station, the last departure of the day is at 1:30PM. The best company by far is TurBus (www.turbus.cl) that has movies and comfortable seats. When you travel this way to get towards Las Leñas you must spend 1 night in Argentina in Mendoza or San Rafael on the way to Las Leñas and take a bus the next morning. Two options:
1. If spend the night in Mendoza you take the Iselin bus that leaves at 6AM the next day (buy ticket the night before) from the Mendoza bus station to San Rafael and then catch the Iselin bus that leaves from the San Rafael bus station to Las Leñas at 9:30 AM.
2. If after arrival in Mendoza bus station you decide to go directly from there to San Rafael, you buy a ticket for the 9;30 AM bus to Las Leñas for the next day upon arrival and spend the night in San Rafael. There is the hostel La Esperanza 3 blocks to the right of the bus station at Avellaneda 263 and across from the bus station 30 meters Hotel Atuel (** 2 Star) Coronel Suarez #130.
Please see our Getting There sections From Mendoza and From San Rafael for more info and Mendoza and San Rafael sections for more information on hostels and accommodation.
If renting a car (please do not rent a car, you will be at the border forever with problems), please make sure you have the proper papers that say you are allowed to bring the car in and out of Argentina from Chile. This is not very straightforward and automatic as you think. Be very clear with the rental company that you want to bring it in and out of Argentina. Crossing the border from Chile to get to Mendoza overland in a bus, car or van can be one of the biggest junk shows in South America as in a big snow year, this border which is also a mountain pass, is closed crossing both ways if it snows heavily for more than 6 hours. It can also sometimes be closed 2-3 days. One of the reasons it closes is that there is a 30 minutes stretch of road below Portillo Ski Resort (Portillo is 20 minutes from the border) that is very narrow, steep,and has about 40 switchbacks. Traveling on this road is made even more challenging by the fact that this is the road international transport trucks from Argentina, Brazil, Uruguay, all enter Chile on. It is common after storms to see trucks that have fallen off the side of the road. Even when the boarder crossing is open you can also spend hours at the 2 border controls for no particular reason when traveling at customs and security due to people not having passports, smuggling goods in and out, etc.... Warning do not pick up hitchhikers as could turn bad like did to us. If you are in a rental car or in a private van, tip/bribe the customs guy $10 USD so you can just go by without him checking too many of your bags, seriously.
The most comfortable and convenient(obviously more expensive) way to get to Mendoza and then onwards to Las Leñas is to fly from Santiago International airport (SCL) to Mendoza International Airport (MDZ). The 2 airlines that offer this flight (2 daily) are LAN (www.lan.com) and Aerolineas Argentinas (www.aerolineas.com.ar). The flights range from $120 USD one way to $240 USD round trip. You can buy tickets at the actual airport as well if you really have to get to Mendoza or Santiago and the pass/border is closed and need to fly out that day. Obviously there has to be availability.
Mendoza Airport (MDZ): Francisco Gabrielli International Airport, 8 km from the city centre, phone number: +54-261-5206000