There are four basic ways to get to San Martín de los Andes:
By plane:
San Martín has multiple airlines that offer flights to Buenos Aires, southern Patagonia and northern regions of Argentina. The fares tend to change often and without notice so it is best to book flights well in advance. Smaller flights have also been known to be canceled without notice in Argentina, so make a few follow-up calls when your departure time nears. The airport is located outside of town and requires a taxi or bus ride into town center.
Airlines:
S M de los Andes / Chapelco (CPC),
Av. San Martín 866 (galería) locales 6 and 8
Av. San Martín 881-Local 3
(02972) 425275

Aeropuerto Chapelco
(02972) 428388
swinds@smandes.com.ar

AUSTRAL
Information and reservations
0810 222 (VOLAR) 86527

SM Andes
Cap. Drury 876
(02972) 427003 / 7004 / 8389

T.A.N. - LAPA
Av. San Martín 941
(02972) 429357 / 428206

LADE
Av. San Martín 915
(02972) 427672
chapelco@lade.com.ar
By bus:
San Martin’s bus terminal may have the best location in the world: across the street from Lago Lácar. This hopping central location is home to various bus services which can take you to destinations across Chile and Argentinia. For Chilean service to Temuco look for Igi-Llaima and Empresa San Martin (be sure to get a window seat on the left side for views of Volcan Lanín). El Petróleo has a road/water route to Valdivia as well as routes in the summer to Osorno and Puerto Montt. If you are staying on the Argentine side of the border, the Ko-Ko bus service passes through the famous Seven Lakes Route. You can find all of the bus companies at the bus terminal on the corner Villegas and Juez del Valle.
Bus Services:
Igi-Llaima
Villegas and Juez del Valle, Box # 6
(02972) 428100

Ko-Ko
Villegas and Juez del Valle, Box # 1
(02972) 427422

Chevallier
Villegas and Juez del Valle, Window # 1
(02972) 427422

By boat:
There is a boat excursion with Plumas Verdes that departs from the Muelle de Pasajeros (passenger’s dock) on Avenida Costanera. The trip takes you into Chile via the Paso Hua Hum (Hua Hum Passage). Due to schedule changes it is mandatory to check with either the Plumas Verdes office or the tourist office for prices and departure times.
By car:
There are two routes into San Martin with a car; the smooth road and the dirt road. Each has its own benefits and drawbacks. The dirt road is the much-talked about Seven Lakes Route. It is currently in the restoration phase, with paving to be scheduled around 2012. The road has recently become much easier to use than in years past and is double-lane in some places. Take note that, since it's a dirt road, you can't navigate it at any significant speeds. This passage through the Andes is one you should take if you have time and the urge to explore.
The paved route is special in its own right, with its expansive views of the open steppe and cartoon-like rock formations lining the Ruta 40. It is important to check the status of the roads when traveling in winter.