The match on Saturday in the Japanese city of Kobe will be a reunion of sorts, with Barcelona's current line-up facing ex-teammates Iniesta, David Villa and Sergi Samper, all now Vissel players.
It will be the first time Iniesta has met his former team on the pitch.
"We all feel that it is such an honour to play Barca," Iniesta told reporters through a Japanese translator.
"The team, Barcelona, is special… It will be a very important match for us," he said.
World Cup-winning Iniesta, who lifted 32 major trophies with Barcelona, signed for Kobe last May in a historic J-League deal worth a reported $30 million a year. The 34-year-old was appointed the team's captain in April.
The friendly is Barca's last match in Japan before they head home, and midfielder Sergio Busquets said the chance to meet Iniesta on the pitch "means a lot" to the players.
"Now he is in Japan and having new experiences. But it does not change the fact that he is a very important friend still," Busquets said.
"Now I am giving him these kind words, but tomorrow on the pitch I won't be able to be like this. We will fight with full strength."
The match comes after Chelsea defeated Barcelona 2-1 in their friendly in Saitama north of Tokyo earlier this week in a game that saw the unofficial debuts of World Cup-winning French striker Antoine Griezmann and former Ajax midfielder Frenkie de Jong.
Manager Ernesto Valverde said he wanted to see the new arrivals getting used to playing with the team and hoped for a better result for Saturday's match.