Luang Prabang has an international airport connection that connects with Chiang Mai in Thailand on Thai Air as well as daily flights to and from Vientiane and Sukhothai via on Lao Aviation If coming from Cambodia or Vietnam, it is typical to go first to Vientiane and then take a smaller plane into Luang Prabang. To note: Lao Aviation has recently endured much criticism for its high incidents of crashes and bad budgeting. Lao Aviation uses low altitude turboprop planes, which look rather dinky and travellers complain about a lot of turbulence in travel. In addition, flights are often delayed or cancelled at this airport so travellers should be sure to call the airline and confirm their flight before travel.
Once arriving in Laos, there are Tuk-tuks and motos available at the airport for the $10 trip into town. Also, some hotels (like the Villa Santi) arrange for shuttle pickup on arrival at the airport.
Some more adventurous travellers may opt to drive into Luang Prabang. From Vientiane, the roads are all paved. However, there are risks with safety and the US state department has issued warnings against robbery on road travel in Laos.
There are boats which travel up and down the Mekong, for instance from Thailand as well as Vientiane. If on a speedboat, it takes about 3 hours to get North to Luang Prabang. However, for safety purposes, it is better to stick with the longer cruises on safer boats.
If you have the time, the slow boat down the Mekong from the Thai border town of Xiang Kong is a wonderful entry to Lao, and gets you perfectly in the mood for the relaxed charm of L-P. The trip takes two days, with an overnight stop at Pak Beng, which has a selection of guest houses. You will share your boat with a wonderful mix of travellers and locals, have plenty of time to read that thick book you haven't opened yet, and have leisurely chats with people from all over the world. A bonus is watching those on the speedboats being bumped around, and those on the few luxury boats looking bored with no-one to talk to. Oh, and there are some gentle rapids! And you have to walk a thin gangplank to get on and off at sand beaches! But this is real travelling down an unspoilt river valley to a wonderful place - Luang Prabang.