Bhutan Tourism Policy,
Travel into Bhutan is regulated by the Government in order to minimise the negative effects of tourism upon its fragile environment and culture.
All visitors must travel through an authorized Bhutanese agent or its overseas representatives on prepaid and pre-planned itinerary. The basic policy is that tourists other then Indian national pay $200 for each night in Bhutan and this covers accommodation, meals, transport, Guide and and administrative services to obtain visas, permits, flight booking hotels etc. As such there are no limitations (quota) on how many can visit each year but due to limited capacity of travel infrastructure such as hotel rooms and flights to absorb tourists, compounded by high rates, these automatically limits the the number of tourists that can visit at the same time.
Visa and Permits
Most countries issue visas from their embassies abroad and stamp it in your passport, but not Bhutan. Bhutanese embassies abroad cannot issue Visas for travel to Bhutan.
You must apply in advance through a tour operator and receive approval before you travel to Bhutan. The actual visa is stamped upon arrival. You will need two passport-sized photographs and US$20 in cash.

Getting there,
There are only two entry points open to visitors. Most arrive by air at the Bhutan's only airport in Paro. The other alternative is to travel through Indian state of West Bengal and enter at Phuntsholing.

By Air All tourists are required to travel at least one way by Air. Special request for exceptions may be possible depending on the season and special conditions. Bhutan's only airport at Paro is about 2 hours drive from the capital, Thimphu. Druk Air, Bhutan national airline is the only airline flying to and from Bhutan. Normally there are 3 flights a week from New Delhi (via katmandu) and five flights a week from Bangkok (via Calutta or Dhaka)

By Land: The only land entry point for tourists is through Phuentsholing, on the southwestern border with State of West Bengal,India. With the special arrangements, it is possible to exit Bhutan via Samdrup Jongkhar in the eastern Bhutan, bordering the State of Assam. The nearest airport to Phuntsholing is Bagdogra, near Darejeeling. And the nearest airport in assam is at Guwahati, which is about 3-4 hours drive from Samdrup Jongkhar

Travel within Bhutan
Travel within Bhutan is only by motor vehicles or trek. There are no domestic air service, helicopters and does not have a railway track. The only way to see the country is either by foot or by road. Mountainous terrain and winding road restrict the average speed of vehicles to less than 25 miles -40 km per hour.

The time to travel
The best time to visit Bhutan is in the spring and Autumn, when most of the festivals take place and the weather is at the best. This is the ideal time for trekking and for traveling throughout the country. You're likely to get wet no matter the season but avoid the monsoon, from June to August, when an average of 0.5m (1.5ft) of rain pours down in Thimphu and up to 1m (3ft) saturates the eastern hills.

Taxes
If you are departing by Air from Paro, the departure tax is Nu. 300 (approx. US$8). Druk Air tickets costs does not include airport taxes. If you are coming from Bangkok, expect to pay Bhat 500 (about $14), from Kathmandu Rs. 500 (about $7) from Delhi or Calutta, pay Rs. 150 (about $4) You can expect to pay no other taxes during your stay. Hotels and restaurant in Bhutan charge 10% sales tax and 10% service charge. Since you meals and accommodations are covered in the tour cost, this is absorbed as well. But taxes are applicable for the beverages such as juice, soda, alcohol etc, which are all borne by yourselves.

Currency
Bhutan's currency is Ngultrum (Nu) equivalent to Indian Rupee. One can exchange money at Paro International Airport on arrival or at any of the Govt. Banks, like Bhutan National Bank and Bank of Bhutan. Money can also be exchanged at most Hotels. There are currently no ATM's in Bhutan available for use by tourists, and credit cards are accepted only at selected shops.

Time Zone
Bhutan has only one time zone, Bhutan Standard Time (BST). It is six hours ahead of Greenwich Mean Time (GMT), 30 minutes ahead of India

Altitude
The maximum elevation that you can reach on a Bhutanese road (3140m in the west and 3750m in the east) and is lower than that which causes altitude problems for most people. Besides, these are mountain passes that you cross to get to the next valley and you are only there for brief moment.
Most of the towns and villages where you spend the night are between 2000 – 2900m and it is rare to have individuals who can suffer from altitude problems at these elevations.

Accommodation
There are varieties of hotels in Bhutan but generally speaking tourists are accommodated in tourist standard hotels, approved by Department of tourism. Although there are some differences between them in property, price and services, most of these hotels are not significantly different from one another. Recently some luxury resorts are being built and some are already operational.