Visas are available on arrival for citizens of most countries, and one passport-sized photograph is required. To complete the process, you must pay a fee it makes it much easier if you bring the fees in US dollars: Transit $5, 15 day $25, 30 day $40 or 90 day $100. Make sure that you fill in all of the forms and keep your departure card for when you want to leave. Facilities for taking passport-sized photographs are available near the immigration desk, though it saves a lot of time if they are prepared before arrival. SAARC nationals are exempt from visa fees.
Please note: your luggage is vulnerable entering and leaving this airport. Do not keep anything of value in checked bags, and if you lock the bag, the zipper may be forced open and broken. No security for you bags.
There are no trains to Kathmandu, renting a car without a driver is not a reasonable option. You can hire bikes in Kathmandu and ride up, but you need to be brave. Alternatively, catch a bus. Check with other travellers to find a safe bus company Green Line & Golden Travels have been recommended, some are quite dangerous and travel at stupid speeds through mountain passes. Many hotels will pick you up from the airport if you give them advanced notice. Otherwise, you can use a pre-paid taxi the stand is on your right as you come out of baggage reclaim/arrivals.
By bus
Kathmandu has frequent and cheap bus service to nearly all parts of Nepal, unfortunately due to poor roads and frequent delays the buses are some of the slowest and least comfortable in South Asia.
Connections include India usually Patna, Gorakhpur, Varanasi or Lucknow and other parts of Nepal such as Chitwan National Park and the trekking hubs of Pokhara to the west, Langtang to the north and Jiri to the east of Kathmandu. For points of departure in India or Tibet see the Nepal 'Get in' section. Buses arriving from the Indian border, Pokhara and Chitwan terminate either at the bus station at Balaju at north of the city or Kalanki at the south of the city since large vehicles and long distance vehicles are not allowed to enter the city due to traffic congestion. From there, there are 'mini buses' which criss cross the main roads of the city for about NPR 20. Varanasi to Kathmandu & Kathmandu to Varanasi INR. 1200 per seat.
The bus to or from Pokhara takes 7-8 hours to cover the 200km. Traffic jams often occur on the zig-zags just out of the KTM valley. All the tourist buses now stop for lunch and snacks at prearranged restaurants. It can be nerve-wracking to look out the front bus window while traveling, due to the narrow roads and much weaving in and out of cars, scooters, & buses. There are many of what westerners would call "close-calls", but they are normal in Nepal and the drivers stay calm through it all. It's best to avoid looking out the front window. There are countless, extremely beautiful sights to be seen while looking out the side windows.
By plane
Kathmandu's Tribhuvan International Airport IATA: KTM, (http://www.tiairport.com.np/) is the largest, and only international airport in Nepal. Most flights to Kathmandu arrive via Delhi, gulf countries UAE & Qatar, or Bangkok, and of the remaining only a few originate from outside Asia. International airlines serving Kathmandu:
Malaysia Airlines (day 2,4,6)
Biman Bangladesh Airline
DhakaAir Arabia — Sharjah.
Air China — Chengdu.
ArkeFly — Amsterdam.
Fly Dubai — Dubai.
Druk Air — Paro and Delhi
Etihad Airways — Abu Dhabi.
Gulf Air — Bahrain.
Dragon Air — Hong Kong
Indian Airlines — Delhi and Kolkata.
Jet Airways — Delhi, Mumbai.
JetLite former Air Sahara, now low-cost subsidiary of Jet Airways — Delhi.
Korean Air — Seoul.
Pakistan International Airlines — Karachi.
Nepal Airlines — Bangkok, Delhi, Dubai, Hong Kong, Kuala Lumpur, Osaka, Singapore and Shanghai.
Silk Air — Singapore.
Thai Airways — Bangkok.
Qatar Airways — Doha.
RAK Airways — Ras Al Khaimah, complimentary bus shuttle service between Ras Al Khaimah International Airport and neighbouring emirates Dubai, Sharjah... .
GMG Airlines — Dhaka.
China Southern Airlines — Guangzhou.
China Eastern Airlines — Kunming.