The event ran along the same winding course the Marathon has followed for many decades—26miles 385yards (42.195 km) of roads and city streets, starting in Hopkinton and passing through six Massachusetts cities and towns, to the finish line beside the Boston Public Library, on Boylston Street in Boston's Copley Square. There was rain early in the day and, by the time the races started, the temperatures were at around 40 °F (4 °C) with gusty winds.
The men's race came down to a sprint finish down Boylston Street. Two-time winner (2013 and 2015) Lelisa Desisa held a slight edge on Lawrence Cherono, with Kenneth Kipkemoi close behind. Cherono edged closer, then on the final block, both men started to sprint, virtually shoulder to shoulder. In the final few steps as Cherono gained a small edge, Desisa gave up the chase and walked over the finish line behind Cherono. It was the closest finish for the men's race since 1988.
Worknesh Degefa took control of the women's race early, surging away from the field eight kilometers into the race, despite having only seen the course before on a YouTube video; she had not done a training run on the course. By the 30 km mark, she had opened up an almost three-minute lead on the chasers. Edna Kiplagat sprinted down Heartbreak Hill in an effort to catch Degefa, narrowing the gap to 42 seconds by the finish.
The field of racers for the Men's Wheelchair race included the 18 most recent winners of the event, but was won by first-time champion, 20-year-old Daniel Romanchuk. He became the first American to win the event since 1993, and the youngest winner ever. Masazumi Soejima of Japan took an early lead, but Romanchuk pulled ahead at mile 16 and won in 1:21:36, an American record. Four-time champion Marcel Hug of Switzerland took third. Romanchuk has won all three of the American majors, having won the most recent marathons in both New York and Chicago as well.
The wheelchair races were made difficult by the morning rain, which had made the first half of the course wet. 2017 winner Manuela Schär of Switzerland took an early lead in the race that she never surrendered, winning in 1:34:19. Five-time champion Tatyana McFadden was close behind her early in the race before hitting a railroad track that cuts across the course, causing her wheelchair to flip upside-down. Despite falling back to sixth place when she overturned, she later rallied and regained position to take second.