In February 2017 he sentenced to six years and three months, having been found guilty of syphoning off millions of euros from the not-for-profit Noos Foundation
Urdangarin, 50, who was stripped of his royal title of the Duke of Palma, appealed the sentence to the country's Supreme Court, which has the power to confirm, overturn, cut or increase the term.
On Tuesday, the long-awaited appeal verdict upheld Urdangarin’s conviction but reduced the jail time by five months to five years and 10 months, according to court sources widely reported in the Spanish media, although no official confirmation from the Supreme Court has yet been made.
Urdangarin could still launch an appeal to the Constitutional Court but has not yet indicated whether he would do so.
A court in the Balearic Islands found Urdangarin -- who remained at liberty during the appeal process -- guilty of taking millions of euros between 2004 and 2006 from a non-profit foundation he headed in the island of Majorca. He was also fined €512,000 ($585,000).
Cristina was tried on charges that she helped her husband evade taxes, but the 52-year-old princess was acquitted.
Prosecutors had initially sought a jail term of 19 years and six months for Urdangarin, a former Olympic handball player.
The corruption scandal involving Urdangarin, which broke out in 2010, sparked outrage when Spain was going through a devastating financial crisis, becoming a symbol of an elite out of touch.
It soured the end of the reign of king Juan Carlos, who gave up the throne in June 2014 hoping his son Felipe VI could freshen up the monarchy's image.
Urdangarin and Cristina have been excluded from all of the family's official public appearances since the scandal erupted. They now live in Switzerland.