Napoli signed Romelu Lukaku from Chelsea.

Romelu Menama Lukaku Bolingoli is a Belgian professional footballer who plays as a striker for Serie A Napoli and the Belgium national team.

Arsenal signed Mikel Merino from Real Sociedad.

Mikel Merino Zazón is a Spanish professional footballer who plays as a midfielder for Premier League club Arsenal and the Spain national team.

Juventus signed Teun Koopmeiners from Atalanta.

Teun Koopmeiners is a Dutch professional footballer who plays as a midfielder for Serie A club Juventus and the Netherlands national team.

Brighton signed Georginio Rutter from Leed.

Georginio Lucius Rutter is a French professional footballer who plays as a forward or attacking midfielder for Premier League club Brighton & Hove Albion.

AC Milan signed Emerson Royal from Tottenham.

Emerson Aparecido Leite de Souza Junior, known as Emerson Royal or simply Emerson, is a Brazilian professional footballer who plays as a defender for Serie A club AC Milan and the Brazil national team.

Chelsea signed Pedro Neto from Wolves.

Pedro Lomba Neto is a Portuguese professional footballer who plays as a winger for Premier League club Chelsea and the Portugal national team.

Manchester United signed Matthijs de Ligt from Bayern Munich.

Matthijs de Ligt is a Dutch professional footballer who plays primarily as a centre-back for Premier League club Manchester United and the Netherlands national team.

Manchester United signed Noussair Mazraoui from Bayern Munich.

Noussair Mazraoui is a professional footballer who plays as a full-back for Premier League club Manchester United and the Morocco national team.

Roma signed Manu Koné from Borussia Mönchengladbach.

Emmanuel "Manu" Kouadio Koné is a French professional footballer who plays as a midfielder for Serie A club Roma, on loan from Bundesliga club Borussia Mönchengladbach.

West Ham signed Carlos Soler from Paris Saint-Germain.

Carlos Soler Barragán is a Spanish professional footballer who plays as a midfielder for Premier League club West Ham United, on loan from Ligue 1 club Paris Saint-Germain, and the Spain national team.