Rail
From Hanoi it is a 9-hour train journey to Sapa.
Vietnam Rail operates some of the cars, but other cars in the train are operated by private companies (Tulico, Ratraco, Fansipan, Friendly and Victoria Hotels, and many others). Some of these cars are significantly nicer than the standard cars. You may need to arrange with a travel agency to get tickets on these tourist cars, but any traveler can purchase tickets for the VNR cars at the Hanoi train station. Warning: several of these cars are not significantly better than standard Vietnamese sleeping cars though, and still substantially more expensive. Pumpkin second class is actually a VNR car booked via this company. Even Pumpkin first class only has a squat toilet (although a sign above the toilet door says: "western style toilet"!).
Cheaper tickets, especially in hard sleeper class, can be hard to come by at times, as tour companies and travel agents will snap up these to first on their own customers (too frequently a promised soft sleeper berth will turn into a hard sleeper when it comes time to board). To avoid rip offs better go to the train station by yourself and get the ticket from the ticket office. This is the only way to make sure that you will get what you have paid for. Travel Agencies in Vietnam are known for their bad business practice. Although one cannot be assured of finding a place, it is often possible to arrive at the station a short while before boarding time, as there are usually young men hanging around trying to hawk unfilled berths at the last minute. The price of these tickets will fall dramatically as departure time draws near.
Prices vary according to both the type of seat purchased and the season during which you are traveling. The times around Vietnamese holidays are particularly expensive and tickets cannot be assumed available for same day
