Illegal taxi cab drivers have for decades run rampant at New York City’s major transportation hubs, despite tight regulations on who can charge people for car rides across the five boroughs.

A new report from Gothamist reveals taxi “hustlers” who swindle tourists into unlicensed, overpriced cab rides are on the rise at JFK Airport as the Port Authority struggles to crack down on the scheme.

“The most important tip: No matter where you are in NYC, if someone is asking you if you need a ride, it's illegal,” said city Taxi and Limousine Commission spokesperson Jason Kersten. Not even TLC-licensed drivers are allowed to solicit rides: Either they’re prearranged, or you’re hailing a cab yourself.

But TLC officials note there are other ways to spot a scam cab.

TLC-licensed cars have specific markings

Yellow cabs have a four-digit medallion number on their roofs and sides, as well as on tags in the backseat. That number should match the city-issued medallion bolted to the front hood of every yellow taxi. The medallion gives yellow taxis the exclusive right to pick up hails — where a rider raises their hand — on any street in New York City.

At the city’s airports, the medallions also give taxis the right to take rides from official taxi stands. For each trip, yellow taxi drivers are required to run a meter to determine the fare.

Green cabs are only allowed to make pickups in Northern Manhattan and the outer boroughs, and similarly have a designated license number on their vehicles.

Passengers can prearrange a pickup of a green cab through an e-hail app at the airports, but can’t catch one at a taxi stand. A green cab trying to make a pickup that isn’t pre-scheduled at a city airport is breaking the rules, according to the TLC.

Cars operating for apps like Uber in New York City must have official license plates bearing the logo of the city Taxi and Limousine Commission

“High volume” for-hire vehicles — the cars operating for apps like Uber and Lyft — are easily identified by their license plates, which typically start with the letter ‘T’ and end with the letter ‘C’. The only legal way to call one of these cars is through a TLC-licensed app. And every one of those cars has a small “T&LC” symbol at the bottom of their license plate.

And if your Uber or Lyft driver’s name or license plate doesn’t match the one provided on the app, it’s a sign the driver might be running a hustle — or at the very least that you got into the wrong car.

If a yellow or green taxi isn’t running its meter or doesn’t have one at all, the ride isn’t legal.

A lack of a taxi meter is a surefire sign a cab isn’t licensed in the city, according to the TLC website. If a taxi driver starts driving without the meter running, they might be trying to overcharge for the ride.

TLC officials instruct passengers to leave the vehicle and report it to 311.

There are certain locations where illegal cab drivers are more prevalent.

Illegal cab drivers are more likely to solicit rides at airports, train stations, concert venues, sporting events, tourist attractions, Broadway shows and hotels, according to the TLC. Officials warn riders to only use the official channels, no matter how convincing a cabbie might be when trying to get you to enter their car.

More drivers are asking passengers to pay for their fare with Square devices (a tap-to-pay device disconnected from the meter)

If a taxi driver says their credit card reader or meter is broken, they could try to overcharge you with their own mobile charging device, like those made by the company Square. Those tap-to-pay transactions are off-record and fees aren't taken out of the driver’s pay.