San Diego and Tijuana Combo Tour with Optional Harbor Cruise. Combine a city tour of San Diego with a jaunt across the border to Tijuana for an excellent overview of these two border cities. Explore San Diego highlights such as Old Town, Balboa Park, the Gaslamp Quarter and Seaport Village, traveling by bus with photo stops throughout the tour. Have time to walk around at some spots before heading over to Tijuana and shopping for Mexican goods on your own. Complete the experience with an optional upgrade for a 1-hour cruise on San Diego Harbor. Book San Diego and Tijuana Combo Tour with Optional Harbor Cruise From $77.99.