The 48-year-old coach has reportedly left the club via mutual agreement just a couple of hours following the 4-1 pre-season friendly loss to Bristol City on Wednesday.
"I absolutely love the football club and that will never change," said the Englishman after the defeat.
Howe took over at the helm of the Magpies in November 2021 after replacing Steve Bruce, managing to lead the side to their first domestic cup [EFL] victory in 70 years and qualification to the UEFA Champions League after a 19-year absence.
According to the Athletic, Howe told the club that he wants to take a break after almost five years in charge following a disappointing 2025/26 season, with the club losing key players like Anthony Gordon and Sandro Tonali during the current transfer window.
The Toons are reportedly close to completing a deal for German mentor Matthias Jaisle to take over as the club's new head coach for the new season.
The 38-year-old Jaisle will vacate his role as Saudi Pro League outfit Al Ahli's head coach to pursue his new role in the English Premier League.