Booking a one-way ticket sounds liberating, doesn’t it? Until you land at your destination and find that you’re anything but free—trapped at the airport, denied entry at passport control.

I’ve booked more than 30 international flights across five continents and, most of the time, I’ve reached my destinations successfully. However, there have been times I’ve been denied entry upon landing at the airport or, en route to my destination, discovered that I needed specific documents that I most certainly did not have. These types of experiences are, in a word, nightmares.

Don’t repeat my mistakes. Here’s what you should know before booking a one-way ticket anywhere.

1. Be aware of the country’s visa requirements for entry.
This one’s a rookie mistake and even applies to travelers with return tickets. Once, heading into Memorial Day Weekend, I booked a spontaneous flight to Russia. Only after I’d purchased my ticket did I think to look up the visa requirements and realized that I did, in fact, need a visa to enter the country—a visa that I wouldn’t be able to procure overnight. It takes anywhere from two business days to six weeks to get a visa for Russia, depending on the type you need. I was forced to call the airline immediately and cancel my trip; fortunately, I called within 24 hours and was fully refunded.

A similar situation happened to me in Indonesia but, instead, I’d already landed there before I found out that I needed a visa to leave the airport. Luckily, I was able to purchase a visa for about 50 bucks at the airport and continue on my way.

To avoid visa complications, always go to a country’s government site to check their requirements, which vary by length of stay and the purpose of your visit. You can do this easily by simply searching “visa requirements for Americans traveling to X” in your preferred search browser—just select the source that ends in .gov so you can be sure that the info is legit.

2. Understand the type of working visa you need if you plan to get a job there.
If you’re booking a one-way ticket because you’ve landed a job some place or are planning to find a job some place, you’ll probably need a working visa of some kind. Let’s look at New Zealand as an example since, post college, I decided to apply for a Working Holiday Visa there before accepting my first job in New York City instead.

If you go to New Zealand’s official government website, it’ll tell you what your work visa options are based on whether or not you already have a job offer, where you’re a citizen and how old you are. For most American citizens with job offers already, options include everything from a Skilled Migrant Category Resident Visa (for people with skills, experience and qualifications for New Zealand to grow its economy), the Essential Skills Work Visa (for those offered full-time jobs in New Zealand by employers who’ve already checked if any New Zealanders were available to do the work), a Specific Purpose Work Visa (for those who have skills or expertise that’ll benefit New Zealand), a Post Study Work Visa (for recent graduates who studied in New Zealand and were offered an opportunity to work in the same area as their qualification) and more.

Of course, the visa requirements are different if you don’t yet have a job. You can apply for visas if you’re the partner of someone holding a working visa in that country; you can apply for similar business, study and skilled work visas as those who’ve already received offers; and you can also check out the Working Holiday Visa, which would allow you to work or study in New Zealand for 12 months. Just remember that, if you have already obtained a Working Holiday Visa but you haven’t used it, you cannot apply to get a second visa. For me, this means that I can’t apply for another Working Holiday Visa in New Zealand.

3. Determine if you’ll need proof of onward travel.
I recently booked a one-way ticket to Bangkok to give the whole digital nomad thing a shot. I only booked my flight there because I’m not sure how long I’d like to stay—maybe a few weeks, maybe a few months. When I told my friends and family about it, all but one of them expressed nothing but excitement for me. While this one friend was still elated, she was the only one to warn me that Thailand is a country that requires proof of onward travel. Countries do this because they want to make sure visitors don’t try to just move there on a tourist visa and never leave.

In other words, you cannot enter the country without another ticket out of the country at some point—they don’t so much care where you go after, but they do care that you leave. And they often put this responsibility on the airlines to check because, if they don’t check and you get to your Point B and immigration officials refuse your entry, the airline is responsible for the costs of deporting you.

If I hadn’t known this, I would have either shown up at John F. Kennedy airport in New York and been forbidden to board, or I’d have shown up at Bangkok’s Suvarnabhumi Airport and been forced to either fly home or purchase an outbound ticket to elsewhere on the spot. This ticket would probably be quite expensive as I wouldn’t have time to compare flights or destinations on aggregator sites, and it would have certainly thrown me for a loop in terms of my plans—or lack thereof.

A few other countries that require documented proof of onward travel are Peru, New Zealand, the United Kingdom, the United States, the Philippines, Indonesia and Brazil. It’s important to note that some countries won’t accept a bus, train or ferry ticket—they want to see another legitimate flight. The good news is, once you’ve reached Southeast Asia or Latin America or wherever, flights are a lot cheaper between countries than they are if you’d be flying from the States.

If you do need proof of onward travel but don’t want to commit to that travel plan, buy a budget airline ticket (read: AirAsia, EasyJet, Ryanair, etc.), or buy a refundable ticket and cancel it once you’ve entered (just be careful of cancelation fees). You can also use credit card airline miles if you have them, since those are more easily refunded or transferred.

4. Be prepared for possible taxes and fees.
I wasn’t aware that you could be hit with entry and exit taxes and fees until I visited El Salvador. When I landed, I went through passport control with no problem. I thought I was on my way out until I hit immigration, which held me up for hours. I was told that I hadn’t yet paid my taxes. In other words, I hadn’t obtained a tourist card upon arrival, which is another $10 USD fee. Because I was supposed to have paid this already, the airport crew passed me from staff member to staff member trying to figure out with whom I should speak and how I could pay.

On my way out of El Salvador, I was also required to pay an exit tax, which cost me $38 USD. This should have been included in my airline ticket but, again, I evidently hadn’t yet paid it. There are also exit fees for leaving the country by sea or land, which varies by point of departure. According to American Express, other countries that require entry and exit fees include Argentina, Belize, Bolivia, Chile, Colombia, the Dominican Republic, Guatemala, Nicaragua and the Philippines. Some of these fees are only paid once and are then valid for years on end, some of them are paid when you purchase your ticket and others are paid at the airports.

If you’re traveling on a one-way ticket, you probably plan to spend ample time on the road, on a budget. Make sure you set aside money for these fees, which can add up to upwards of a few hundred bucks.

5. Compare the cheapest routes.
If you’re looking to go to Bangkok, like me, chances are that you want to head straight there—though I recommend taking advantage of layovers, since they can essentially be free rides to new places. And the most direct route isn’t always the cheapest route. My flight, for example, flies to Taipei, Taiwan, where I have a quick two-hour layover before I hop over to Bangkok. I booked this flight not only because there were no direct flights to Bangkok, but also because flying to Taipei and then Bangkok was cheaper than flying to, say, Phnom Penh, Cambodia and then Bangkok.

Consider all major capital cities in neighboring countries, as capital cities typically have the busiest airports. Busier airports, on average, offer cheaper flights than smaller airports simply because they work with more commercial airlines and have more traffic coming in and out, which means more flight options for you. Use a flight search engine to plug in different nearby cities to which you can fly, and then hop on a much shorter (and therefore cheaper) flight to your final destination from there. It’ll require a bit of math, but it could save you some serious dough.

My go-to websites for flight hunting are Momondo.com and SkyScanner.com. Momondo is, in my humble opinion, the single best flight aggregator to search for multicity travel; it offers you the option to search one-way, round-trip and multicity flights even using the destination “take me anywhere,” which allows you to check out airfare in the cheapest cities given your specified dates. The multicity option allows you to swap cities in and out to determine the cheapest routes, which is ideal for this scenario.

Sky Scanner is another travel metasearch engine with a flexible airfare search option through which you can search “everywhere” as your flight destination. You can also explore specific dates, entire months or the “cheapest month,” and Skyscanner will pull up a list of all cities in ascending order of cost. Before booking your one-way ticket, consult either of these sites to find the cheapest one-way ticket you can find—even if that means it has more than one leg.

Photo: iStock/Getty Images Plus/YakobchukOlena