For Foreign tourists, one must obtain the ILP (Inner Line Permit) which can be get done at All India Missions and Sikkim Tourism Offices in New Delhi and Kolkata. For Indian nationals, one does not need any permit unless you’re planning to visit a protected area or go on trekking to the restricted passes in the RAP and PAP regions, from Tourism Department at Gangtok. Apply at least 3 months in advance and always carry a Voter ID, Driving License, passport, or any other identity proof.