Medan's Polonia International Airport and Belawan sea port are both visa-free and visa-on-arrival points.
For more visa information, see the Indonesia page.
By bus
The central station for all larger buses in Medan is Amplas Station Central not located in the center of the city though. This is where a lot of the smaller minivans go as well, and where travellers need to go to make connecting buses to further cities. Many of the large air-conditioned buses perform overnight routes.
Larger, non air-conditioned buses and large luxury buses often Mercedes that are air-conditioned some have toilets on board, though they are squatting toilets that are difficult to use when the buses are moving, given driving habits and road conditions throughout Sumatra.
As an example of prices from August 2005, expect to pay around Rp 50,000-80,000 for an 8-10 hr overnight luxury bus without toilet saves about Rp 10,000+ trip, as in to Duri, Bukit Lawang, or Lake Toba Danau Toba. Such buses provide a small snack and sometimes have televisions on board. While seats are very comfortable by Sumatran standards, all rides are swervy/bumpy and drivers often play stereos quite loud during the entire trip unless a movie is available. Also, many buses have smoking sections in the back, and sometimes, smoking occurs in the front of the non-smoking section by the driver if the driver is so inclined. Earplugs are good accessories. Furthermore, while the large luxury buses have ample stowage above seats, keep valuables safe while you sleep.