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Elon Musk has floated the idea of building a high-speed tunnel between Austin and San Antonio. Musk laid out the idea on X, the social media platform that he owns. He said it could serve as a precursor to a hyperloop that would link the two cities in less than 30 minutes.
The Boring Company, which Musk also owns, said on X that it would be interested in building the project.
Joey Pawlik is the executive director of Activate SA, a transportation advocacy organization that calls on city leaders for a comprehensive transit plan. He says Musk’s idea is one of several proposals aimed at easing congestion along Interstate 35, including passenger rail between Austin and San Antonio.
“I think it’s an interesting proposal, if and when it would happen. But again, I know there's lots of capital funding involved in getting across different jurisdictions. So I think if you can pull off, that'd be great. But I mean, I’ll believe it when I see something like this could happen,” Pawlik said.
In his social media posts, Musk provided no timeline or other details about how the idea would move forward. The plan would call for speeds of up to 200 miles per hour.
The Boring Company alluded to being able to travel from Austin to San Antonio to visit a restaurant for the day. The comments were part of a thread that started with an AI-generated video about futuristic communities.
It’s not the first push by Musk to create a more efficient pathway between the Alamo City and the state capital. Nor is it the only project proposed to alleviate the growing congestion along I-35.
A study commissioned by Travis County estimated that building a rail line between Austin and San Antonio would cost between $40 million to $80 million per mile for the track, among other costs.
“These separate capital cost items calculate to around $13.5 billion in 2026 dollars for a potential commuter or higher-speed (up to 125 mph) passenger rail system between Austin and San Antonio using the existing SH 130 and I-10 rights of way,” the study said.
Previously Musk had pitched a similar plan in 2022 about an 80-mile tunnel between San Antonio and Austin. He also suggested a tunnel between San Antonio’s airport (SAT) and downtown that would be served by Tesla vehicles.
While neither of those ideas panned out, a rapid transit corridor along San Antonio’s San Pedro Avenue to connect the downtown to the northside is currently under construction. VIA Metropolitan Transit’s Green Line is anticipated to be completed by 2028
“That's a huge, monumental step for San Antonio to have better, faster transit for a city in our region, and we've been waiting for this a long time," Pawlik said. "There's ways that can be improved even more to cut down on wait times, but I think this is a huge first step to having better mass transit in San Antonio.”
Musk floated another tunnel plan under Houston last year to address flooding. The Texas-based billionaire has undertaken several ventures in the Lone Star State such as Space X which is headquartered near Brownsville. The Boring Company is headquartered in Bastrop east of Austin.
