What is the first thing you do before planning a trip out of the country? Check airfare, hotel rates, and best times to go? There is something else you need to do that could make all of those things irrelevant: check on visa and passport requirements. Everyone knows they are going to need a passport to enter a foreign country, but visas are a different matter, and equally important.
A visa is an endorsement or permit issued by the country you are visiting, that enables you to travel to that country. If the country you plan on visiting requires a visa, and you do not have one, you will be denied entry into the country. Visa requirements are not universal, and foreign countries will often require visitors from certain countries to obtain visas, but not others.
There are many reasons that countries such as the USA require visitors to obtain visas. For starters, they want to know who is in their country. Acquiring visas, provides extra screening and background checks, and the ability to verify against international "No-Fly" databases. At times, the information on file from the visa can be used to control entry into countries and to locate a traveler for various reasons including personal, legal, etc..
Generally, a visa is stamped in a passport, and so, the Embassy or consulate will require your passport to affix the visa. If your desired foreign country doesn't have a consulate near you, you may have to mail your passport to them, which makes a lot of people a little nervous. Keep in mind that it can take anywhere from several seconds/days to several weeks to get your visa. Sometimes visas are obtained upon entry, but often they must be obtained weeks before.
Each country that requires a visa has its own requirements, fees and application forms. In general, in order to get a visa you will need a passport with at least six months validity left on it, an application form that is filled out with various information, and a fee, ranging from $20 to several hundred dollars. You often also need two passport photos.
Travel planners and visa service companies can answer questions and assist you with getting the right forms, but at the end of the day, your visa, much like your passport is your responsibility. I recommend using a private third-party company for tourist visa services; if you select a good company, they are more than worth the $50 or so fee that they charge. They are always faster than going through the consulate directly, and have more accurate tracking of your visa application. My company, Zoom Vacations, has had great experience working with Travisa, a visa expediting company. To begin, go to Travisa's website.
Since all countries have different passport and visa requirements, with different fees and processing times, this needs to go into your planning from the beginning. It could take you several weeks to obtain a visa, acquire extra pages for your passport, or to obtain a passport with a later expiration date. And trust me, not having a visa when it is required is not the type of thing that you can talk your way out of. With a little planning you can get a visa easily and be on your way.
And, whether or not the country you are visiting requires a visa, your passport should have at least two blank pages and should be valid for at least six months after your planned departure from the country you are visiting. Some countries will not let you in if your passport does not meet this criteria, and your passport itself should be in as pristine condition as possible. Yes, technically a country can deny you entry if your passport is damaged, although it would have to be severely damaged for this to generally be enforced.
Lastly, check also for vaccinations that may be required to enter or pass through any given country. Check the Centers for Disease Control and Prevention website to see what the requirements are for the destination(s) you plan to visit.