Domestic travelers caught with weed in Chicago airports won’t be busted after Jan. 1, Chicago police say.

Even though marijuana will still be illegal under federal law — and it’s illegal to carry across state lines — authorities have no intention of arresting people caught with the drug at Chicago airports, officials said Friday.

That’s because the federal Transportation Security Administration, which screens all passengers getting on planes, says it will defer to police if they find someone carrying pot.

“Our officers are not looking for cannabis as they go through their normal security [check]. But should they come across it, we are going to contact the Chicago Police Department to make a final determination on the disposition,” TSA deputy federal security director Louis Traverz said at the news conference.

And Chicago police, while advising against traveling with the drug, say they won’t arrest you if you aren’t carrying more than what’s allowed under the new law. Starting Jan. 1, adults 21 or older in Illinois can possess up to 30 grams of cannabis flower, 500 mg of THC in a cannabis-infused product and 5 grams of cannabis concentrate. Half those amounts are allowed for non-residents.

“To ensure safe travel for all travelers, we’re encouraging all travelers not to bring cannabis through Chicago airports as it remains illegal under federal law,” Chicago police commander William Mullane said. But if travelers are “within the guidelines of our current statute, starting Jan. 1, we can’t enforce anything. If they’re legal, they’re legal.”

Nor will cops take your pot.

“If it is not a violation of the statute or ordinance, we would offer them a proper disposal of the cannabis if they wish, or they could continue on with their travels,” Mullane said.

Still, officials warned pot-carrying travelers to be aware of the laws in the states where they are traveling to. And public consumption of the drug at the airport will still get you into trouble.

Airlines also have their own rules prohibiting pot.

“Federally, with some few exceptions, marijuana is still illegal,” United Airlines spokesman Charles Hobart said in an email. “We follow federal law and do not permit carriage.”

International travelers, at least those coming to Chicago, won’t have it as easy.

Customs agents will continue to enforce federal law for travelers entering the U.S., according to Steven Bansbach, spokesman for U.S. Customs and Border Protection.

Travelers caught with weed at U.S. customs may face “denied admission, seizure, fines, and apprehension,” Bansbach said in a statement.