Shojaei who is an attacking midfielder has made 15 appearances for Iran's senior side. He comes to the La Liga club as a free agent since his contract with the UAE side Al Sharjah had expired.
According to the club's official website, Shojaei signed a three year contract.
"We have been involved in a dialogue with Osasuna for a year, and an initial agreement was reached about two weeks ago, and the final agreement was signed today", said Shojaei's agent Mahmoudreza Fazeli.
"We provided Osasuna with tapes of Shojaei's recent performances with the Iran national team. They also consulted midfielder Javad Nekounam before making their final decision."
Club officials announced that Shojaei will be officially introduced to the club and the fans in July prior to the start of their preseason training.