Uber riders in San Diego can now cross the border and head into Tijuana.

But don’t expect a return trip from the company just yet.

Uber said its drivers will start shuttling riders from California to Mexico on Friday.

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The ride-hailing app is already available in both Tijuana and San Diego (along with nearly 400 other cities around the world), but getting from the U.S. to Mexico in a single car was impossible until now. Riders would have to cross the border on foot, and then request a new car in the new country.

The new system, dubbed UberPASSPORT, will make the U.S.-Mexico hike a thing of the past. But for now, the cross-border service is allowed only on U.S.-to-Mexico trips, not the other way around. Bloomberg says that’s because the service is regulated at the point of pickup.

Travelers hoping to get back into the U.S. will have to hail one Uber in Tijuana, ride to the border, hop out and walk across, and request an American Uber to pick them up on the other side.

Uber tells Fortune the California-Mexico trips are a “first step” toward more international cross-border rides.

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Earlier this week the company also launched a new standalone app for food delivery, UberEATS, which is available in about half a dozen cities around the U.S. So if you don’t have your passport spring-break ready, you can still order up a little Mexican chow to-go, even if it’s not quite as good as the real deal.

 

Update (Mar. 18 10:06 a.m. E.T.): This story has been updated with a comment from Uber.