Dirang is on NH-13, the main road from Bomdila (40 km south) to Tawang (135 km north). Most travellers come up from Guwahati or Tezpur in Assam, a two-day drive with a night in Bomdila or Bhalukpong.
Shared sumos (jeeps) run daily from Tezpur and Bomdila and continue on to Tawang. The road climbs spectacularly via Sela Pass (4,170 m) on its way to Tawang — sometimes blocked by snow in midwinter.
You need an Inner Line Permit to enter Arunachal Pradesh; arrange it in Guwahati, Kolkata, or online before you set out. There is no airport in Dirang itself; the nearest is Tezpur in Assam.