"A lot of people don't know visas exist, or they think U.S. citizens don't need one," says Diane Kakoz, manager of B&K Express in Southfield, Mich., a passport-visa expediting service.
"A lot of people going to Brazil get to the airport there and get sent back." A visa is a travel document some nations require in addition to the passport. Getting one usually costs $80 to $140, plus processing fees.
That expense can be a rude shock to individual travelers on a budget. But on a group trip, it is usually an invisible cost folded into the tour price.
Some nations let tourists get a visa when they arrive. Others, like Venezuela, accept tourist cards instead, handed out on arriving flights. While some visas take weeks to process, Cambodia and Australia offer visas online with near-immediate approval.
Luckily, U.S. tourists can blithely traipse around most of the world with just their passports. In fact, Americans can travel to 169 nations without a visa. That makes us among the freest travelers in the world.
The people least free to travel without a visa? Afghans.
The reason some nations' travelers need visas and others don't is simple. Richer countries tend to make people from poor or war-torn countries get visas as an extra step to make sure visitors return to where they came from. Poor countries are more likely to admit people from rich countries without visas.
Whatever the requirements, the biggest mistake visa seekers make, experts say, is procrastinating.
"Everybody waits until the last minute and then wastes money to get a rush visa," says Abraham Jacobi, consular liaison at Perry International in Chicago, which expedites travel documents. Applying one month ahead is good. Wait until the week you're leaving and you'll likely pay a rush fee of up to $200.
Part of the problem is that you may not even know if you need one. Tourists, business travelers, students or those who plan to work each need specific visas and should check the rules (to find out if you need a visa, look up a country at travel.state.gov and view "entry and exit requirements"). Even then, the process can be convoluted.
AMONG VISA QUIRKS:
*Russia issues visas only for exact dates. Travelers who don't depart on time can face weeks of delay getting out of the country.
*Cruise passengers stopping in Brazil need visas or they can't get off the ship. It must be obtained ahead of time, as many a disappointed cruise passenger has discovered too late.
*More countries are requiring that your passport be valid for at least six months beyond your planned return date. And if you need a visa, you will need at least one blank page in your passport so the visa can be attached, Jacobi says.
Many tour operators obtain visas for their clients. If you need to do it yourself, consider hiring a visa expediter to do the legwork.
An expediter tells you what documents you need, what fees to pay and hand-delivers the documents to a consulate for processing. It then gets the visa and documents back to you.
Expediters charge a fee, commonly $45-$90, on top of the actual cost of the visa -- but it may be worth it. Some reputable visa expediters include: B&K Express Passport and Visa Services (248-262-1600, bandkvisas.com), Perry International (312-372-2703, perryvisa.com), Travisa (202-463-6166, travisa.com) and VisaHQ (800-345-6541, visahq.com).
WHAT YOU NEED TO GET A VISA
*Payment for the visa and the expediter processing fee.
*In some cases, a letter from your sponsor or trip-provider, plus a contact in-country. In other cases you might need to show a driver's license, birth certificate or copy of your airline ticket/itinerary.
FREEDOM TO TRAVEL
These nations rank best in how many countries their citizens can visit without a visa:
Denmark, Sweden, Finland -- 173 countries
Germany -- 172
United Kingdom, Italy, France -- 171
Japan, Spain -- 170
United States, Ireland -- 169
These nations rank worst in how many countries their citizens can visit without a visa:
Afghanistan -- 24 countries
Pakistan -- 31
China -- 40
India -- 53
Russian Federation -- 89
Source: Henley & Partners Visa Restriction Index Global Ranking 2011