I checked potential reservations (rate quotes) for Tijuana with Alamo, Avis, Hertz,
National and Thrifty websites - All quotes had unlimited km and none listed any restrictions for taking the rental car between the two countries.I contacted reservation reps from Alamo , Avis , Hertz (links open in new windows))and National to see if they knew of any such geographic
restrictions for rentals originating in Mexico. None was aware of any, but all agents suggested that you confirm with an employee of the specific rental car location in Tijuana that you would potentially rent from to see if there were any problems with taking a rental car between Mexico and the United States.
The quote from
stated "Only rentals from the Cities of Tijuana, Mexicali and Monterrey are allowed to
cross the border into USA and need to purchase additional liability insurance at a cost of US$6.00 per day."