Dutch goalkeeper Tim Krul became Norwich's seventh signing of the 2018 pre-season when he joined on a free transfer on 24th July 2018. The 30-year-old was a free agent after leaving Brighton and Hove Albion, where he played just five first-team games after joining from Newcastle in August 2017.

Krul started his professional career at Newcastle United in 2006, having previously played for the team's youth academy, as well as ADO Den Haag and RAS youth teams. Initially third choice behind Shay Given and Steve Harper, Krul made his Newcastle debut in the UEFA Cup game on 2 November 2006, away to Palermo. He spent the 2007–08 season on loan to Falkirk, and the following season on loan to Carlisle United, making 26 and nine appearances respectively. He broke into the Newcastle first team in the 2010/11 season.He eventually became first choice, totalling 185 appearances.

He suffered an ankle injury in 2015/16 and lost his first team place. He spent the 2016/17 season on loan to Ajax.to provide him with top-tier football as he continued his recovery from injury. That deal was cut short after Krul had played six games for the club's reserve side, and in January 2017, he joined fellow Eredivisie side AZ Alkmaar on loan for the rest of the season

On 31st August 2017, he joined Brighton reuniting with former Newcastle manager Chris Hughton. He made his debut on 19th September in the EFLCup against Bournemouth

Krul represented the Netherlands at every level from the under-15s to the under-21s between 2002 and 2011. He made his debut for the full national team in July 2011, and was part of their team that came third at the 2014 FIFA World Cup.In the quarter-final against Costa Rica, he was brought on by Louis van Gaal as a 120th-minute substitute for the penalty shootout. He saved two of the five penalties he faced as the Netherlands won 4–3.That was the first time in the history of the World Cup that a goalkeeper was sent in as a substitution solely for penalty shootouts. At the time of his move to Norwich, he had eight international caps.

Krul made his Norwich debut on the opening day of the 2018/19 season in a 2-2 draw at Birmingham City. He made 46 appearances in 2018/19 as Norwich won the Championship and promotion to the Premier League.

Krul was the winner of the Barry Butler Player of the Year award for 2019/20, despite a disappointing season which saw the Canaries relegated with three matches still to play, on a record low points tally. However, the 32-year-old has been the standout player for Daniel Farke’s team, showing consistency and leadership throughout, with very few errors in spite of City’s defensive injury problems and lack of top-flight experience throughout the campaign. He is only the fifth goalkeeper to win the award. He played 38 games in 2019/20.

Krul won his first international cap for five years when he played for Netherlands against Mexico on 7th October 2020, which the Dutch lost 1-0. This was his ninth cap.

He made 37 appearances in the 2020/21 season as Norwich returned to the Premier League by winning the Championship. He was also named in the Netherlands' provisional squad for the Euro 2020 Championships to be held in 2021.

He made 31 appearances the following season as Norwich finished bottom of the Premier League. This included his 150th game for the clun.

On 21st August 2022, it was reported that Krul was on Manchester United's radar as back-up for goalkeeper David de Gea. Other keepers on their shortlist include Watford's Daniel Bachmann and Borussia Monchengladbach's Yann Sommer

He made 17 appearances for Norwich during the 2022/23 season.

According to football reporter Alan Nixon on 30th July 2023, Norwich are willing to sell goalkeeper Tim Krul this summer after he lost the starting spot to Angus Gunn. With a year left on his contract, it is said that Krul has been given the green light to leave Norwich City this summer. He is reported to be one of the club's highest earners and Norwich would hope to bring in a transfer fee. Krul finally moved on 17th August 2023 joining Premier League newboys Luton Town. He will compete alongside Belgian Thomas Kaminski, who arrived at Kenilworth Road this summer from Blackburn Rovers. Krul made his Hatters' debut on 29th August 2023 in a 3-2 win over Gillingham in the Carabao Cup.

Krul had played 169 games for Norwich. "Tim has been an outstanding servant for Norwich City," sporting director Stuart Webber told the club's website . "He has been a top class goalkeeper and leader during his time with the club."