RedBus operates a bus from Gangtok to Paro every 4 hours. Tickets cost $8 - $12 and the journey takes 4 h 30 min. 2 other operators also service this route.
How to get from Gangtok to Paro
From Gangtok taxi to Bagdogra airport, fly to Paro airport, then drive to Paro. 2 h 31 min $209. From Gangtok bus to Siliguri, taxi to Siliguri, bus to Phuentsholing - Bhutan Post, Mini Bus to Thimphu, then drive to Paro. 17 h 56 min.