The 11 biggest under-21 transfers

The biggest and best football clubs from around the world are all trying to find the next superstar as they look to secure signings for the future.

Taking a gamble on a young, up-and-coming talent is often expensive, as the players below show. But which youngsters were signed for the largest sums? With the help of Transfermarkt data and news reports from the time, we’ve trawled through the archives to determine the most expensive under-21 signings.

For this list, players had to be aged 20 or less at the time of their transfer, with all fees used including potential add-ons.

11

Anthony Martial

Monaco to Man Utd (£58m)

In joint-9th place is Anthony Martial after he joined Manchester United in September 2015 from French side AS Monaco.

At the time, the forward became the most expensive teenage footballer, as he joined the Red Devils when he was 19 years old. The Premier League side paid £36m for the forward, but the deal agreed could have risen to £58m with various add-ons included.

Martial played 317 times for United during his nine years at Old Trafford, and scored 90 goals despite struggling to be a consistent performer.

10

Christian Pulisic

Borussia Dortmund to Chelsea (£58m)

Christian Pulisic joined Chelsea after a £58m move from Borussia Dortmund in January 2019.

At the time, the USA international was 20 years old, and didn’t join up with the Premier League side straight away, as he spent the rest of the 2018/19 season on loan at Dortmund.

Pulisic spent four years at Stamford Bridge, during which he played over 140 games and was a part of the sides that won the Champions League, the UEFA Super Cup and the FIFA Club World Cup.

9

Romeo Lavia

Southampton to Chelsea (£58m)

Romeo Lavia also made a £58m move as a teenager when he joined Chelsea from Southampton in the summer of 2023.

The Blues have paid an initial £53m for the midfielder, but that could rise by a further £5m in add-ons. Lavia joined Chelsea at the age of 19, and the Premier League side have had to bide their time integrating him into the first team, as his first campaign was hit by injuries.

8

Leny Yoro

Lille to Man Utd (£58.9m)

Leny Yoro joined Manchester United during the 2024 summer transfer window, signing from Lille in a deal worth £58.9m – £6.73m of which comes in add-ons.

Yoro signed a five-year contract at Old Trafford in what was described as a coup for the Red Devils, as the French defender had looked set to join Real Madrid.

Unfortunately for Yoro, his United career got off to a slow start due to an injury he picked up in pre-season, but he is now starting to get to grips with his new team.

7

Joao Neves

Benfica to PSG (£60m)

Joao Neves also made a move in 2024, as he joined Paris Saint-Germain from Benfica in a deal worth £60m. The French champions have agreed to pay £50m upfront and then a further £10m in add-ons.

The Portugal international only moved into Benfica’s first team 18 months before his move to PSG, but at 19 years old, he has become one of the most expensive youngsters in football. Neves has become a key member of Luis Enrique’s team, and he has already won his first trophy for the French giants, picking up the French Super Cup at the start of the season.

6

Rasmus Hojlund

Atalanta to Man Utd (£72m)

Rasmus Hojlund is the third Man Utd player on this list, as the Red Devils gave £72m to Serie A side Atalanta to secure his signature. United agreed to pay an initial £64m with a further £8m coming in add-ons.

Hojlund joined United as a relative rookie at the top level, as the 20-year-old had not long established himself in the Atalanta first team. United obviously saw enough for them to bring him to Old Trafford, but it has been a frustrating time for the forward, as he’s yet to really find his groove in front of goal, scoring 23 goals in 71 games in all competitions at the time of writing.

5

Matthijs de Ligt

Ajax to Juventus (£76.5m)

Making the top five for the most expensive youngsters is defender Matthijs de Ligt, as he joined Juventus from Ajax in 2019 for a fee of £76.5m when he was just 19 years old.

The Netherlands international moved into the spotlight as he played an important role in helping Ajax reach the Champions League semi-final the previous season.

There were several teams chasing his signature, but Juventus won the battle. However, it was a signing that didn’t quite pan out well, as De Ligt was sold to Bayern Munich three years later. However, he will be pleased with his time in Turin, as he won Serie A, the Italian Cup, and the Super Cup.

4

João Félix

Benfica to Atlético Madrid (£113m)

João Félix was only 19 years old when he made the move from Benfica to Atlético Madrid in a deal worth a staggering £113m.

This deal for Atlético was a club-record fee and saw the Portugal international become one of the most expensive signings in football history. Unfortunately for Felix and the Spanish side, it was a move that didn’t really work out, as while the forward was very much a part of the team in his first few seasons, he struggled to make an impact in front of goal.

He then had loan spells at Chelsea and Barcelona, and now finds himself back at Stamford Bridge on a permanent basis. Fortunately, there will be a fond memory he can take away from his time at Atlético Madrid, as he helped them win La Liga in 2021.

3

Jude Bellingham

Borussia Dortmund to Real Madrid (£115m)

Jude Bellingham is arguably the most high-profile player in football right now, and his move to Real Madrid played a big part in that. The midfielder joined the Spanish giants from Borussia Dortmund in June 2023 in a deal worth £115m, with Madrid paying an initial £88.5m, with the transfer reaching £115m with add-ons.

Bellingham has taken to life in Spain very well and has already filled up his trophy cabinet, as the Englishman won La Liga, the Spanish Super Cup and the Champions League in his first season.

The 21-year-old was also named Player of the Season in Spain last year, and his move to Madrid has not only improved his domestic career but has put him on the international stage, as he’s become a key player for England.

2

Ousmane Dembélé

Borussia Dortmund to Barcelona (£135.5m)

Coming in at second place for the most expensive youngster is Ousmane Dembélé, who joined Barcelona from Borussia Dortmund in a deal worth a potential £135.5m back in 2017.

The winger cost the Spanish giants an initial £96.8m, with the fee rising to £135.5m including add-ons. At the time, Dembélé became the second-most expensive signing in football, behind Neymar’s £200m move to PSG. The Frenchman spent six years at Camp Nou, playing 185 games, and was able to win three La Liga titles, two Spanish Cups and two Spanish Super Cups.

Since the move to Barcelona, Dembélé has since moved to PSG, where he will be looking to add the Champions League to his trophy cabinet.

1

Kylian Mbappé

Monaco to PSG (£165.7m)

It may come as no surprise to see one of the best footballers in the world right now, Kylian Mbappé, is the most expensive youngster.

An 18-year-old Mbappé joined PSG in September 2017, with the transfer seeing the Frenchman join PSG on a season-long loan deal before signing on a permanent basis a year later as PSG activated the option to pay £165.7m.

Mbappé produced some stellar moments in a PSG shirt, with him playing 308 times for the French giants, scoring 256 goals and recording 106 assists. His best season in front of goal came in the 2021/22 season, where he scored 28 goals and registered 19 assists.

The Frenchman picked up several trophies during his time at PSG, winning Ligue 1 six times, four French Cups, two French League Cups, and three Super Cups. He also won the Golden Boot in France six times and was named Footballer of the Year in France three times, the last coming in 2022.