Transit fares are going up on Sunday, meaning straphangers will collectively be paying $300 million more each year for service that’s getting more crowded and less reliable.

On fare hike day, the Riders Alliance, the Community Service Society, and the rest of the “Fair Fares” coalition will rally at noon outside Barclays Center to call on Mayor de Blasio to fund half-price MetroCards for the 800,000 New Yorkers who earn below the federal poverty line.

More than two-thirds of the City Council has signed on to the Fair Fares campaign since it launched a year ago. But Mayor de Blasio declined to include the $212 million needed for the program in his preliminary Fiscal Year 2018 budget, arguing that the state should cover the cost since the governor controls the MTA.

Governor Cuomo shouldn’t escape scrutiny: His refusal to pay for system maintenance without borrowing massive sums is causing transit fares to rise faster. But the coalition has targeted de Blasio both because he campaigned on reducing inequality and because they believe it’s within the city’s means.

Sunday’s rally starts at noon. At 1 p.m., advocates will head into the station to talk with riders and collect their thoughts on sticky notes (a spin on the well-known post-election art installation at the Union Square station).

Police conducted 29,000 arrests for fare evasion in 2015, according to the Police Reform Organizing Project. For undocumented immigrants, those arrest can lead to deportation.

CSS President David Jones told City Council members last month that the arrests are like prosecuting people for stealing bread. “This is a kind of insanity going on in this city, particularly because of the great wealth here, that we’re starting to make a priority of people who try to evade a fare as if they are major criminals.”