The 29-year-old, formerly of Benfica, has secured a temporary switch to their great Portuguese rivals in a bid to get his career back on track.
Muito feliz por ter a oportunidade de jogar neste grande clube pic.twitter.com/pLjty4mc8k— Fabio Coentrao (@Fabio_Coentrao) July 5, 2017
Coentrao, who made just six appearances for Real last season, had revealed the move on Twitter on Tuesday before the two clubs followed up with official statements confirming the deal.
In a picture with his family taken from Sporting's Estadio Jose Alvalade stadium, he wrote: "Very happy to have the opportunity to play for this great club."
Real's statement read: “Real Madrid C.F. and Sporting Clube de Portugal have agreed the loan of the player Fabio Coentrao until 30 June 2018.”
Coentrao won one Primeira Liga and two Taca da Liga titles during his time at Sporting's arch rivals Benfica before joining Real for €30m in 2011.
He featured regularly for the Blancos between 2011 and 2013 before seeing his game time become limited.