The 35-year-old, a devoted father from Wythenshawe, was in Benidorm with friends before City were due to kick-off at the Estadio de la Ceramica.
Bradshaw was discovered deceased in bed by a friend early Tuesday morning. The family has been informed that there are no suspicious circumstances, although the cause of death has not yet been confirmed.
Man City have since released a statement following his tragic death, saying: "We are deeply saddened by the passing of Guy Bradshaw, a City supporter who tragically died in Spain before the Club’s match against Villarreal last night.
“Everyone at the Club sends their condolences to his family, friends, and fellow fans during this difficult time. Once a Blue, Always a Blue."
A GoFundMe page has also been set up to help return his body to the UK and support his young daughter.