The MTA is on schedule to provide Wi-Fi in all 279 of its underground subway stations by the end of the year, amNewYork has learned.

As of Tuesday, more than 250 stations have been equipped with the service through Transit Wireless, the company contracted with the agency to provide Wi-Fi throughout the system, according to a source familiar with the project.

The progress will represent a successful completion under an accelerated timeline established by Gov. Andrew Cuomo, who has championed outfitting the state-run agency’s subway and bus system with cell and wireless internet service as a way to bring the MTA “into the 21st century.”

“Today’s world demands seamless communication and we challenged the MTA to accelerate implementation of this project because the need for connectivity doesn’t end when riders head underground,” said Cuomo in a statement. “Modernizing the MTA and delivering technology riders need is about setting ambitious goals and meeting challenges head on — and that’s exactly what we’re on track to accomplish here.”

December will mark the end of the five-year rollout in the world’s largest subway system that began in 2011. Originally, the MTA and Transit Wireless had set a goal to complete the work by the end of 2017, but this past January Cuomo announced that the work would be finished a year early. At that point, about 140 stations had been equipped with Wi-Fi.

Sarah Kaufman, assistant director for technology programming at the NYU Rudin Center for Transportation, said that building wireless connectivity in the subway is a huge boon for riders looking to be more productive underground, to navigate around transit interruptions, and to reach emergency services.

“It’s recognition of the fact that the phone is the most important development in transportation since the building of the subway,” said Kaufman. “With our phones we can navigate the city much differently than we did 20 years ago, so it’s a game changer.”

Connected stations can be identified by blue stickers adhered to platform columns and tiled walls. Despite some connection kinks, riders thumbing their phones in the Herald Square station said they enjoyed the level of service thus far.

Will Ferdinand, 24, a native Brooklynite from East Flatbush, said that connecting through Transit Wireless is a much smoother process than using similar free Wi-Fi services offered in restaurants and coffee shops.

Ferdinand said he paid close attention to the rollout. As a subway busker who sings on the D train, he’d stop in stations to use Wi-Fi when he was tight on cell phone data.

“It’s a real convenience,” said Ferdinand, sitting on a platform bench, with phone in hand and an acoustic guitar on his back. “And it’s pretty quick. You tap connect and — boom — you’re connected.”

Maria Goldverg, a 28-year-old from Ridgewood who works in publishing, said she was more inclined to use her data when available.

“The Wi-Fi is good, but you have to re-log on when you travel from station to station,” she said. Transit Wireless did not respond to a request for comment, but on the company’s website, it said it hopes to eventually bring Wi-Fi to riders on trains traveling within tunnels.

Using her phone during her commute has become part of Goldverg’s daily routine. She appreciates being able to check work email, read the news and let her boss know if her train is delayed. On second thought, she laughed, “sometimes, I still like to take a break from my phone on the train.” (With Bazona Bado)