The picture postcard was in its heyday in the early twentieth century. Every image in this "Postcard Tour" is a postcard either from the Exposition or the groundbreaking ceremonies in 1911. Not included here are the many other views of San Diego and California sold with Exposition logos to promote the Exposition. Manufacturers produced hundreds of different postcards. A few postcards were made for both the Panama-California and the Panama-Pacific Exposition, held in San Francisco, held also in 1915.

There was a postcard shop on "The Isthmus" and postcards were widely sold elsewhere as souvenirs. Postage to destinations within the U.S. was one cent. The U.S. Government operated a post office on the Exposition grounds in the Commerce and Industries Building. Exposition Station postage cancellations were made only at this post office.