There are three principal ways of arriving to Mérida – by plane, by bus/car and recently by train. The airport is located just south-west of the city centre and there is a direct bus (VayVen, 45 pesos) which will take you to the main bus station and then into town finishing up at Paseo 60. Taxis cost about 100-200 pesos and it takes about 15-30 minutes depending on the traffic.
The bus station for ADO is located is about 6 or 7 blocks south from the central plaza. The walk is about 10-15 mins. Buses depart and arrive to the neighbouring cities of Valladolid (also Cancun) and Campeche hourly or more frequently. The buses are modern, clean, comfortable and generally good value for money.
Finally another way to arrive to Mérida is by train. The new Tren Maya goes from Cancun to Palenque in Chiapas. En route it stops at Merida. At present there are about 3 departures in each direction daily but this may increase in the future. The train is relatively new and modern but the stations for almost all locations are situated far outside of the city (Valladolid, Mérida, Campeche). The ride is very scenic and relaxing but not particularly quick taking into account getting to and from the stations. The fares vary depending on the whether the passenger is Mexican or foreigner.