There are two options for getting to Bhutan. One is flights to Bhutan and another is overland travel to Bhutan. Bhutan is a landlocked country and no seas touch Bhutan, so entering Bhutan by sea is out of the question.
Bhutan by air
The most common and popular means of getting to Bhutan is by air. Bhutan is connected with several cities in South Asia and you can’t directly fly to Paro Bhutan other than these cities. These cities include Kathmandu to Paro flight including you also flies to Paro from New Delhi, Bangkok, Singapore, Dhaka. Only two airlines operate direct flights to Paro Bhutan with sometimes one transit. They are Druk Air (the national flag carrier) and Bhutan airlines (a private company). Paro International airport is the only international airport in Bhutan. It’s considered one of the world’s most beautiful airports located inside the Paro Valley at 1.5 miles above the sea-level surrounded by the majestic Himalayas.
Entering Bhutan by land
The most preferred way of entering Bhutan by road from India if coming from the west is at the border town between India and Bhutan, Phuentsholing. Phuentsholing is closer to Bagdogra airport in the city of Siliguri West Bengal in India where one can fly from Delhi or Calcutta. Travelers then drive to Phuentsholing from Bagdogra and enter Bhutan overland. One can easily connect with Darjeeling, Kalimpong or Sikkim in West Bengal from Phuentsholing. From Nepal, Kakarbhitta is the Nepal-India border from where the road connects Phuentsholing with Nepal. Kakarbhitta can be reached upon flight from Kathmandu to Bhadrapur or Biratnagar. The other two entry points to Bhutan overland is Gelephu if you are traveling from the central region and Samdrup Jongkhar to enter the Dragon Country from the east. From Samdrup Jongkhar you can connect to Guwahati in India from where flights operate to Delhi, Calcutta or Mumbai. Train is also available to different cities in India from here. Though Bhutan shares it’s border with Tibet but no entry points have been opened up till now.