Bart Nieuwkoop

Nieuwkoop played in the academy of Tholense Boys (nl) before joining the academy of RBC Roosendaal.

Feyenoord

In 2011, Nieuwkoop joined the academy of Feyenoord, where he signed his first professional, three-year contract in April 2014. He made his first-team debut on 4 October 2015 against De Graafschap starting in the first eleven and was replaced after 68 minutes by Tonny Vilhena. On 16 November 2015, Nieuwkoop extended his Feyenoord contract with three years, to mid-2020. Having played as a midfielder in the academy, he was mostly used as a right-back at the first team. On 24 April 2016, Feyenoord beat FC Utrecht 2–1 in the final to win the KNVB Cup, but Nieuwkoop did not play in the competition. Nieuwkoop made his European debut on 15 September 2016, getting subbed on for Rick Karsdorp in injury-time of a 1–0 win against Manchester United in the UEFA Europa League group stage. He made just one appearance in the first half of the 2016–17 Eredivisie season, but started six of Feyenoord's final seven matches as Feyenoord won the league title for the first time in 18 years. In the deciding 3–1 win against Heracles Almelo on 14 May 2017, he gave the assist for the first-minute goal of Dirk Kuyt with a throw-in. Ahead of the 2017–18 season, Nieuwkoop changed his squad number from 26 to 2 after the departure of Karsdorp. He missed the first part of the new season, including the won Johan Cruyff Shield against Vitesse, due to an injury, gaining competition for the…

Nieuwkoop made his debut for the Netherlands under-17 on 25 October 2012, replacing Stijn Spierings during a goalless draw against Lithuania in the 2013 UEFA Euro qualifiers. He later played for the Netherlands at under-18, under-19 and under-20 level. On 11 October 2014, he scored for the under-19 team in a 3–0 win against Moldova in the 2015 UEFA Euro qualifiers. Nieuwkoop played his only game for the Netherlands under-21 on 22 March 2018, as a substitute for Denzel Dumfries at half-time of a 1–4 friendly defeat against Belgium.

Club

As of match played 15 March 2026

Nieuwkoop was born in Bergen op Zoom on 7 March 1996. He is a son of a father and his mother Petra Nieuwkoop and a brother of Sam and Koen Nieuwkoop. He grew up in Tholen and later started living in Bergen op Zoom and Rotterdam with his girlfriend Susan den Houting. He called himself a "family man". Nieuwkoop played tennis for a few years as a kid and worked as a dishwasher before playing for Feyenoord. His daughter Zoé Nieuwkoop was born on 9 September 2020.