When approached for comment, the IAM pointed Business Insider to a statement it issued on Monday night.
"This contract also creates a new foundation to build on for the future and that future begins today," Jon Holden and Brandon Bryant, presidents of IAM districts 751 and W24 respectively, said in a joint statement on Monday.
"We are ready to help Boeing change direction and return to building the highest quality and safest airplanes in the world," the statement added.
The win, which also includes a $12,000 ratification bonus, comes after Boeing machinists shot down two other offers since September 13.
The first was when over 30,000 union workers voted to strike after being displeased with the 25% pay increase they were originally offered.
"This agreement represents a new standard in the aerospace industry — one that sends a clear statement that aerospace jobs must be middle class careers in which workers can thrive," Brian Bryant, IAM's international president, said in a statement on Monday.
New Boeing CEO Kelly Ortberg, who started in August, can also fully implement his culture turnaround plan as union factory employees return to work.
"While the past few months have been difficult for all of us, we are all part of the same team," Ortberg said in a message to Boeing employees on Monday seen by BI.
"We will only move forward by listening and working together. There is much work ahead to return to the excellence that made Boeing an iconic company," he added.
According to a Bank of America analyst estimate, Boeing lost about $50 million a day due to the strike.
This has snowballed the problems at the already embattled planemaker, which started with a door plug blowing off a new 737 Max in January. That was followed by a safety audit, a CEO change, and at least three whistleblowers who reported quality concerns on the assembly lines.