Reyes' coffin, drapped in the flag of his boyhood club Sevilla, was carried through the streets of his hometown of Utrera before the funeral service at a local church.
The 35-year-old former Spanish international died Saturday in an accident on the main road from Sevilla to Utrera.
The crash and resultant fireball also claimed the life of one of his cousins while another passenger was still in hospital Monday, according to police.
Images from the scene of the crash show the burnt-out car flipped on its roof.
Daily newspaper Diario de Sevilla reported Reyes was driving over 200 kilometres (125 miles) per hour at the time of the accident while sports daily Mundo Deportivo, citing a police report, said he was going at 237 kilometres per hour.
Contacted by AFP, a spokesman for Spain's Guardia Civil police force which is investigating the accident declined to comment on the reports.
On the day of the crash former Spanish international Santiago Canizares criticised Reyes, who reportedly owned a fleet of high-powered cars, for driving at high speed.
“Speeding is a reprehensible attitude. There were victims in the accident aside from the driver. Reyes does not deserve a tribute like a hero.
“Nevertheless I regret what happened and that I pray for their souls,” tweeted Canizares, who was part of Spain's national team at the same time as Reyes.
Circular con exceso de velocidad es una actitud reprochable
En el accidente ha habido víctimas además del conductor
Reyes no merece un homenaje como si fuera un héroe
Pero eso no quita que lamente lo ocurrido y que rece por sus almas
Lo intolerable lo encuentro en quien se alegra
— SANTIAGO CAÑIZARES ? (@santicanizares) June 1, 2019
A minute's silence was held for Reyes before Saturday's Champions League final in Madrid between Liverpool and Tottenham.
Reyes shot to fame at Sevilla and was snapped up by Arsenal, where he was part of the unbeaten 'Invincibles' who won the 2003-2004 Premier League title.
Reyes later had spells at Real and Atletico Madrid.
He won the Europa League five times, twice with Atletico Madrid and three times in his second spell at Sevilla.
Reyes played 21 times for Spain between 2003 and 2006, scoring four goals. He also won domestic league titles with Real Madrid and Benfica.