 You cannot board this shuttle at San Diego International Airport, but instead take a local bus from the Airport to the Depot Amtrak Station, 1050 Kettner Blvd.on the corner of Broadway Ave, Downtown San Diego, CA 92101.There is no equivalent shuttle from TIJ airport back to downtown San Diego as most people pay to use CBX and then take private vehicles or Uber or taxis as there is no public transportation from CBX.