Where possible, cross borders as early in the day as possible. Onward transportation tends to wind down in the afternoon and border areas are not always the most salubrious places to hang around late. There is no departure tax when you leave Guatemala by land, although many border officials will ask for an illicit Q10.
Guatemala has official border crossings with all of its neighboring countries. Check visa requirements before arrival.
The busiest and most useful border crossings:
Bus is the most common way to enter Guatemala by land. Most first-class international buses run nonstop from Guatemala City to their destinations. First-class buses for Belize also depart from Flores/Santa Elena. On first-class buses (particularly to Honduras and El Salvador) the driver may take your passport and complete border formalities for you. Going to Belize or Mexico, you will be required to do them yourself. Whatever border fees (official or otherwise) there are will not be included in the ticket price.
Popular tourist shuttles from Guatemala and Antigua include to San Cristobál de las Casas (Mexico), Flores (Belize) and Copán (Honduras).
Second-class buses tend not to cross the border.
The mountain of paperwork and liability involved with driving into Guatemala deters many travelers. You will need the following documents, all clear and consistent, to enter Guatemala with a car:
Insurance from foreign countries is not recognized by Guatemala, forcing you to purchase a policy locally. Most border posts and nearby towns have offices selling liability policies. To deter foreigners from selling cars in Guatemala, the authorities make you exit the country with the vehicle you used to enter it. Do not be the designated driver when crossing borders if you don't own the car, because you and it will not be allowed to leave Guatemala without each other.
Gasoline is readily available in all but the tiniest of villages. If you see a young kid waving a funnel at you, it means he is selling cheap contraband Mexican gas – some people swear by it, others claim that its high sediment content ruins engines.
Mechanics are also everywhere. Authorized agencies can only be found in the larger cities. Generic parts are easy to come by, but if you're looking for originals, Toyota is by far the most popular make in the country, followed (distantly) by Mazda and Ford.