The park has two main approaches.
The eastern side, served by Bukit Lawang, is reached from Medan. Tourist minibuses run direct in three to four hours and are easily arranged through any Medan guesthouse. Public buses go via Binjai and Bohorok and take five to six hours but are much cheaper. Tangkahan is reached on a separate road from Medan, also about four hours.
The western side, around Ketambe and Kedah, is reached from Medan via Kutacane. Buses run daily and take about eight hours; the road is winding and the journey is genuinely tiring. From Banda Aceh on the north coast it is roughly twelve hours via Takengon, through some of the most spectacular mountain country in Sumatra.
There are no public flights to the park, and the central section has no road access at all — you walk in on foot, with a guide, from one of the perimeter trailheads.