Mexico borders "America", the country officially known as the United States of America. Hence, this time could take from a couple of minutes walking, to several hours by car, boat or plane.
It is a total of 21 hours and 54 minutes, or 1343.31 miles. This is if you are driving to Grand Isle, Lousiana, which dips down into the Gulf of Mexico.
Distance from London to Mexico City is: 5561.3 Miles ( 8950 Kilometers / 4829.4 Nautical Miles ) Approximate flight duration time from London to Mexico City is 11 hrs, 33 mins