Yes. If you enter via plane, they will give you a form to fill out on the plane ride. They ask you how many days you plan to remain in the country for-- you just put down the maximum amount of days you plan on sticking around. It just can't be more days than a general short-term visa will allow.
Upon your arrival in Mexico you will stand in a line, hand over the filled out forms and your passport, answer a couple questions they already know the answers to (usually something you filled out on the form), and bid you adeu. If the person who greets you is in an awful mood, they might decide to only allow you to stay a smaller amount of days in Mexico, in which case they'll let you know. That doesn't happen often, from my experience. They are usually friendly and professional.
If you overstay your welcome (stay longer than the indicated amount of days), you'll be charged a fine whenever you do leave the country.
If you want to stay a year, or some other very long period of time, look into getting a long-term visa. You might need a return ticket for that. over 3 years agoAnswered by Valerie via WorldNomads.com