The La Liga January transfer window has officially opened, and clubs across the league have been busy making moves to strengthen their squads ahead of the second half of the season.

One of the most notable transfers in recent weeks was the arrival of Barcelona defender Samuel Umtiti from Paris Saint-Germain for a reported fee of €25 million. The Frenchman had been linked with a move away from the Ligue 1 champions for some time, and his departure will be a significant blow to PSG's defense.

Elsewhere, Real Madrid have signed Brazilian winger Renato Sanches on loan from Manchester United for one year. The 22-year-old has been out of favor at Old Trafford this season, and he is expected to provide competition for the likes of Vinicius Junior and Rodrygo in Los Blancos' attack.

In terms of key signings, Atletico Madrid have brought in former Chelsea midfielder Mateo Kovacic on loan until the end of the season. The Croatian international has made over 400 appearances for Chelsea since joining the club in 2018, and he brings experience and creativity to Diego Simeone's side.

Overall, the January transfer window has seen several high-profile signings and departures across the La Liga landscape. With the second half of the season just around the corner, clubs will be looking to continue their progress and push for silverware. Stay tuned for more updates as the window progresses.