The 27-year-old centre-back, who can also operate at right-back, joined Barcelona from Uruguayan side Boston River in 2018 and has since made more than 200 appearances for the Spanish giants.
Speaking after completing his move, Araujo said he was delighted to join Liverpool and described the transfer as the right step for his career.
"I'm excited to be here at this massive club with lots of history. I'm excited to meet my team-mates, excited to get started playing, and I'm very motivated and really up for getting going," he said.
Araujo added that the move came at the right stage of his career and that Liverpool's interest quickly convinced him to make the switch.
"It was the ideal move for me at this stage in my career. I think it was a move that was necessary for me to take. As soon as I heard that interest from Liverpool, everything went into action really, really quickly," the defender said.
Liverpool have been looking to strengthen their defence following the departure of France international Ibrahima Konate, who left the club to join Real Madrid on a free transfer.
Araujo arrives at Anfield with considerable experience at the highest level. During his time with Barcelona, he won three La Liga titles and two Copa del Rey trophies.
He was also handed the Barcelona captaincy in January following goalkeeper Marc-Andre ter Stegen's departure on loan.
Spanish football commentator Alvaro Romeo previously described Araujo as "a colossus" during Barcelona's title-winning campaign three years ago.
"He was phenomenal in defence and the best defender in La Liga by far," Romeo told BBC Radio 5 Live.
However, Romeo noted that injuries and occasional lapses in concentration affected Araujo's consistency in recent seasons. He believes the defender can regain his best form at Liverpool.
Araujo remains under contract with Barcelona until 2031 but made only 11 La Liga starts last season as the Catalan club won the Spanish league title for the 29th time.
The move gives Liverpool another experienced defensive option as they prepare for the new Premier League campaign.
Spanish football commentator Alvaro Romeo previously described Araujo as "a colossus" during Barcelona's title-winning campaign three years ago.
"He was phenomenal in defence and the best defender in La Liga by far," Romeo told BBC Radio 5 Live.
However, Romeo noted that injuries and occasional lapses in concentration affected Araujo's consistency in recent seasons. He believes the defender can regain his best form at Liverpool.
Araujo remains under contract with Barcelona until 2031 but made only 11 La Liga starts last season as the Catalan club won the Spanish league title for the 29th time.
The move gives Liverpool another experienced defensive option as they prepare for the new Premier League campaign.
Liverpool are scheduled to begin their league season away against Newcastle United on Sunday, August 23, at 16:30 BST.
Disclaimer: Comments and opinions on any part of this website are the opinions of blog commenters or anonymous individuals, and do not reflect Strenuous Blog position.