Medan is Sumatra’s primary international hub, with frequent flights from its new airport to mainland Southeast Asian cities such as Singapore, Kuala Lumpur, Penang and Bangkok. In West Sumatra, Padang receives flights from Kuala Lumpur. Banda Aceh, Palembang, Pulau Batam and Pekanbaru also receive international flights from mainland Southeast Asia.
You can catch a plane from Jakarta to every major Sumatran city with Garuda (www.garuda-indonesia.com), Citilink (www.citilink.co.id), Lion Air (www.lionair.co.id) or Sriwijaya Air (www.sriwijayaair.co.id), among others. Flights from Sumatra to other parts of Indonesia typically connect through Jakarta.
A warning: when palm-oil plantations on Sumatra’s east coast are burnt (annually, usually during dry season), the smoke frequently results in the closure of Pekanbaru and Jambi airports.
Budget airlines have signalled the end of some international ferries, such as the Penang–Medan route. However, on Sumatra’s east coast, ferries run from both Dumai and the Riau Islands (namely Pulau Batam and Pulau Bintan) to both Malaysia and Singapore.
For Malaysia, there are regular services to Melaka, Port Dickson and Klang (for Kuala Lumpur) from Dumai. To Singapore, ferries make the quick hop from Pulau Batam and Pulau Bintan, the primary islands in the Riau archipelago. From Batam and Bintan, boats set sail for Dumai and Tanjung Buton, from where there are buses to Pekanbaru on Sumatra's mainland.
Ferries cross the narrow Sunda Strait, which links the southeastern tip of Sumatra at Bakauheni to Java’s westernmost point of Merak. The sea crossing is a brief dip in a day-long voyage that requires several hours’ worth of bus transport between both ports and Jakarta and, on the Sumatra side, Bandar Lampung.