An underground tunnel has been discovered by Mexican security forces on July 30, but media access to the site was given on Sunday, officials say.
The 123 meter-long tunnel, which ends close to the US border is believed to have been built by the drug smuggling Sinaloa cartel.
The unfinished tunnel has lighting and rails and is possibly intended for smuggling drugs into the US.
An anonymous tip-off led security forces to a warehouse where the tunnel entrance was hidden.
This is the third tunnel found in Tijuana this year.
Last month, head of Sinaloa cartel Joaquín “El Chapo” Guzman escaped from a top security prison through a tunnel, discretely built under his cell that stretches over 1.6 km in length. Mexico is offering $3.8 million for the notorious drug lord.
The Sinaloa cartel is known to smuggle huge amounts of illegal drugs into the United States and across the world. They are one of the parties involved in the violent drug war that has plagued Mexico in recent years.