Mayor Bill de Blasio announced today that the city had reached a tentative agreement with the Corrections Officers’ Benevolent Association that would give the union’s 7,000 members retroactive raises and a contract through 2018.

The $364.7 million deal follows the pattern established with the other uniformed unions—firefighters, police brass, sanitation—trading incremental raises for greater worker contributions to the healthcare fund. Like all municipal unions, COBA, whose members primarily work on Rikers Island, did not have a contract with the city during the last years of former Mayor Michael Bloomberg’s administration, and the mayor trumpeted his success in reaching labor agreements with 94 percent of local public workforce.

“New York’s boldest answer the call of duty every day, and are on the front lines as we work to ensure a safer Rikers, and a safer correction system. This contract agreement provides the fair wages they deserve, while protecting New York City’s taxpayers,” Mr. de Blasio said in a statement.

As with a number of the contract agreements, the COBA contract includes special provisions to address its members’ specific concerns. The Department of Corrections agreed under the deal to form a Rikers Island Central Arrest Unit with the Bronx district attorney’s office to crack down on attacks on guards.

“COBA continues to work diligently and advocate for the best protections and benefits for our membership and their families. We are looking forward to joining with City Hall to create a better working environment, and becoming a part of reform that works on both sides,” said union President Norman Seabrook.

Mr. Seabrook, like several other union leaders, has clashed with the administration at times over proposed reforms. As the city has sought to reduce widespread abuse of prisoners and incidents in which guards participate in smuggling contraband onto Rikers Island, the COBA president has highlighted the frequent assault and harassment his predominantly minority members endure on the job.

The contract will grant 1 percent retroactive raises for every year from 2011 through 2015, then a 1.5 percent raise for 2016. The raise will go up to two and half percent in 2017 and three percent in 2018.

The final raise will also cover the first four months of 2019, so as to finance another special provision of the contract: an arrangement which will allow retiring corrections officers to receive a payment for their unused leave time at the end of their careers.

The deal must still be ratified by must still be ratified by COBA as a whole.