Buying an open bus ticket is one of the most convenient and budget conscious ways to make your way backpacking from north to south (or visa versa) through Vietnam. Almost any tour agency offers them, but not all companies are equal.
PICKING A BUS COMPANY...
Finding a reputable operator is the first challenge. Most promise you the world and don't deliver. Because frankly it doesn't mater if they don't meet your demands or not, you have to pay in cash and there is no chance in getting your money back.
Watch out for the company making too many promises. That's a big red flag. Very, very few buses have bathrooms and if they do, bathrooms may still not be operational.
Even if you buy a ticket with one company, some companies will sell your ride to another company because the fuller the bus, the more money they make.
For the record, I had the "Viet Nhat Sleeper" Open Bus ticket, which basically meant I got an almost fully reclining seat on most legs on my journey.
PREPPING FOR YOUR JOURNEY...
Drink very little before getting on the bus and very little on the bus. No bathrooms. Though the bus driver has stopped about every 2.5 hours so far in my experience.
Grab an extra shoe bag - in case of food poisoning or motion sickness. I won't share my food poisoning horror story with you, to save you from fear of these buses, but trust me on the extra shoe bag.
Pack snacks. When or if your bus driver does stop, they're stopping at a convenience store or roadside restaurant which are especially designed for tourists - so they are about double the price of getting food at a normal spot.
Charge your electronics. Even if the bus company says they will have charging stations, very likely, they will not.
Get noise cancelling headphones - the Vietnamese don't obey typical courtesy - they answer phones, leave ringers on, etc. It's very noisy and you'll want to sleep your way through those night buses.
Take morning buses, this put you in your next city around mid-day, giving you time to check into your hostel and explore.
Bring socks if you are at all concerned about your feet. I gave up on the idea that my feet would be super clean very early on in my journey, but if you're a germ person, you'll definitely want socks for the bus route.
Most buses have cleaned travel-size pillows and blankets for your journey. Luckily, buses are typically air-conditioned, so light layers and use of the blankets are necessary.
Pack your items in one main bag and one small bag. Your main bag/backpack will go in a locked compartment under the bus. You won't have access to it at any point along the ride. Pack your valuables, electronics, snacks, etc. in a small bag to carry on the bus. And I mean small, you'll have very limited space, so you don't want your backpack pushing you out of your seat.
LET'S TALK MONEY...
Pricing for 6 stops (for me in 2016) from Ho Chi Minh to Hanoi was $1.1M Dong, which is approx. $47 USD. I've met people who have spent at little as $40, but aren't very happy with the operator.
Whenever you're looking to buy a ticket, don't just purchase at the first place that you walk up to. Get a couple of prices before deciding who you want to go with.
WOULD I DO IT AGAIN?
Despite the worst food poisoning/night bus incident that you could ever imagine, I have to say, YES. It was a complete part of the backpacking experience. I met so many people with interesting stories, cautionary tales, and travel advice that really helped with the "you're not crazy" part of coping with all my experiences.
The one thing that I wish could be done differently is adding one more stop - Phong Na - which is where the largest caves in the world are! Maybe you can find a company that includes that in their package.
Remember, life is a journey and it is what you make of it. So stay positive and look at these as opportunities for adventure, not frustration.
