The Belgian winger, who will split time between the first team and the reserves, completed the opening part of the session with the rest of the group before continuing with an individual-focused work programme.
He then spoke to reporters pitchside, reflecting on his first taste of first-team life in Catalonia.
"I've had really good feelings. They've welcomed me really well. It's a great family. I have to work hard. I enjoy playing football. I like having the ball at my feet and taking players on one-on-one. I'm here to give everything," said Bisiwu.
The 18-year-old also revealed that Neymar was his childhood idol and that he is now a big fan of Raphinha, and had nothing but praise for Lamine Yamal: "He's a special player. He has great qualities."
Bisiwu signed his contract with Barcelona on Friday, running until June 2031, completing a deal the club had spent weeks preparing with an eye on the future. Barcelona are understood to have paid Club Brugge around €8.5m for the winger, who made 36 appearances in Belgium's second-tier Challenger Pro League for Club Brugge's reserve side, Club NXT, having come through the club's academy after starting out in Leuven's youth ranks.
He becomes Barcelona's third signing of the summer, following the arrivals of England international Anthony Gordon and young German forward Karim Adeyemi, underlining the club's continued investment in attacking talent with a similar profile.
Having completed the paperwork on Friday evening, Bisiwu flew to England to join the Barcelona squad but arrived too late to be involved in the friendly against Birmingham City. On Saturday morning, he reported for training under the coaching staff for the first time, working alongside his new team-mates before switching to the individual session with fitness staff.
A versatile winger
Bisiwu burst onto the international scene in 2025 with his performances for Belgium at the European Under-17 Championship, catching the eye with his pace, dribbling ability and knack for creating danger.
His natural position is left wing, though he can also operate on the right flank, giving Barcelona's attack added versatility as he begins life at Camp Nou competing for minutes behind more established options such as Raphinha.
He also featured in the past two UEFA Youth League campaigns with Club Brugge's youth side, scoring three goals in 14 appearances and helping the team reach the competition final.