Crossing the Border: Samdrup Jongkhar to Darranga & Guwahati
Bhutan Immigration, at the border, is open 7am to 8pm daily. Here you will be fingerprinted and photographed as you enter Bhutan, or just get a passport stamp if leaving Bhutan.
The Indian Foreigners' Checkpoint, where you get stamped in or out of India, is at Darranga, 5km south of the border and is open 24 hours.
Both Bank of Bhutan and Bhutan National Bank in Samdrup Jongkhar will change ngultrum into Indian rupees. In theory you are required to have your original exchange receipt, passport copy and an application form, available in the banks.
Bhutanese banks will not give Indian rupees for US dollars. For small amounts you are better off changing money with your guide.
Onward to India
A taxi to Guwahati or Guwahati's Lokpriya Gopinath Bordoloi International Airport costs ₹4000 and both journeys take around three hours. A taxi to Rangiya (₹800 to ₹1000, one hour) gives access to trains running east and west across India.