The 17-year-old only made his first-team debut for the Catalan outfit in January, but he has developed into a vital player for Xavi's side, now featuring on 20 occasions in all competitions.
Cubarsi has cemented his spot in the middle of the Barcelona back four, but there had been some concern over his future due to the alleged presence of a €10m (£8.6m) release clause in his contract.
Manchester United and Manchester City are believed to be among the clubs keen on Cubarsi, with the Premier League giants said to be monitoring his situation at Barcelona.
However, it is understood that the Spaniard's first choice has always been to sign a new and improved deal with Blaugrana, where he has been since 2018 after initially spending time in Girona's youth set-up.
Barcelona 'close to reaching agreement with Pau Cubarsi'According to Sport, the centre-back's renewal 'is expected to close this week', although the last details will not be finalised until later in the month.
The report claims that the new contract will rise on a yearly basis, although the additional three years, which would take him until June 2029, cannot be officially signed until he turns 18 in January 2025.
Meanwhile, the defender's release clause is expected to rise from €10m (£8.6m) to €500m (£430.4m).
Cubarsi's form for Barcelona this year saw him earn a call-up to the senior Spain squad in March, and he made his debut during the friendly against Colombia.
The centre-back is now in a strong position to be included in the La Roja squad for this summer's European Championship, which officially begins on June 14.
Pau Cubarsi's alleged new deal is big news for Read on sportsmole.co.uk