The 27-year-old, who moves to the Hornets on an undisclosed fee, joined United from Feyenoord in 2014 and went on to make 77 appearances for the Magpies in two years at the club.
Newcastle released an official statement on Wednesday afternoon confirming the Dutchman’s departure. The club wished Janmaat the best of luck for the future: "The club wishes to place on record its thanks to Daryl for his efforts during his time at Newcastle. He leaves with our best wishes for his future at Watford."
Keeper Tim Krul is expected to follow his fellow countryman out of the exit door by joining Ajax on a season long loan. However, with only 12 months left his contract, Krul will sign a new one-year extension before heading to the Netherlands.
Henri Saivet also left the club after moving back to France to join Saint Etienne on a season loan.
First season – fans favourite
Having impressed at the World Cup in 2014, Janmaat was signed as Mathieu Debuchy’s replacement following the Frenchman’s move to Arsenal.
Janmaat enjoyed a fantastic first season on Tyneside. The right-back played all but one of United’s 38 Premier League league where his energetic and attacking performances from the full-back position saw him contribute to six assists and one goal.
His eye-catching performances didn’t go unnoticed as he clinched the North East’s player of the year award to joins the likes of Alan Shearer, Kevin Keegan and Peter Beardsley in winning the award.
Second season – heavily criticised
As the Magpies began their relegation campaign, Janmaat inability to defend became known to Newcastle fans and their opposition. But it wasn’t just his defensive vulnerability has become publicised.
The defender’s attitude began to be questioned as the players slowly became an outcast in United’s relegation run-in. In fact, when Rafael Benitez took over from Steve McClaren, the 56-year-old left the Dutchman out of the squad for the next five games after a bizarre incident that saw Janmaat break his knuckles after reportedly punching a wall in the 3-1 defeat at St Marys.
In the games that Janmaat didn’t feature, United went unbeaten before he returned to start and score in the Toon Army’s final game of the season - 5-1 win against Tottenham Hotspur.
Starting life in the Championship
Janmaat starred in Newcastle’s opening two Championship defeats versus Fulham and Huddersfield. Benitez then dropped the right-back to the bench in the Magpies’ first win of the season at home to Reading before being omitted from the squad for the win at Bristol City.
The 27-year-old ended his spell at Newcastle with an unwanted stat. Apart from the Tottenham game, United were unbeaten in seven of their last eight than the Dutchman didn’t feature in.