The Western Hemisphere Travel Initiative (WHTI) is a US law that requires all travellers, including US and Canadian citizens, to present a valid passport or other approved secure document when entering the United States.
For information on travel documents required for travel to, from or through the United States, please consult the website of the Canada Border Services Agency.
Canadians are not required to carry a passport to enter Mexico. However, in order to avoid delays and misunderstandings, it is strongly recommended that you travel with a passport valid for six months after your arrival date. It is the only universally accepted identification document, and it proves that you have a right to return to Canada.
Most airlines departing from Mexico are now refusing boarding to Canadians returning to Canada without a valid passport. It is strongly recommended that Canadians carry a valid passport for all air travel to Mexico in order to ensure they may board their return flight to Canada.
For more information, please consult the Embassy or Consulate of Mexico in Canada or Foreign Affairs and International Trade Canada's Travel Report for Mexico.