Get a passport or check passport validity
For U.S. citizens, a passport application can take approximately four to six weeks to process. For non-U.S. citizens, check with your consulate for current processing times. Some countries require that a traveler’s passport be valid for six months after the date you enter the country.
To find out what those requirements may be, select your destination country and refer to the “Entry/ Exit Requirements” section on the U.S. State Department Country Specific Information page.
At least 6 months before your trip (or before you consider an opportunity)