By SABC Sport
15th August 2023
The 27-year-old played in all 38 of the Bees' Premier League games last season keeping 11 clean sheets and conceding 46 goals.
He will compete with England international Aaron Ramsdale for the number one position as Mikel Arteta's team look to build on last season's title challenge, whilst also playing in the Champions League for the first time 2017.
Gunners' sporting director Edu said: "We welcome David to us on a season-long loan from Brentford. David is a top-quality goalkeeper, who has consistently performed to a high level with Brentford in the Premier League.
"With David joining us we are adding quality and depth to our squad so we can perform at the highest possible level in all competitions."
He has also signed a new two-year deal with Brentford with an option for a third, something the club has described as a "fall-back option" should his Arsenal move not be made permanent.
Director of football Phil Giles said: "I'm not expecting to see David back at Brentford, although if ever that happened then of course the opportunity to work with such a high-class goalkeeper for up to two more years would in many ways be an unexpected bonus for us.
"All parties (want) to make this a permanent transfer as soon as practically possible."
Raya, who joined Brentford from Blackburn whilst they were playing in the Championship in 2019, leaves having appeared 161 times for the club.
He made his debut for Spain during a 2-1 friendly win against Albania in March 2022 and was a part of Luis Enrique's squad for last year's World Cup.
Tottenham had reportedly been keen to sign him as a long-term replacement for Hugo Lloris but a deal to take him from the Gtech Stadium did not materialise.
Arsenal sold back-up keeper Matt Turner to Nottingham Forest earlier this month, with the United States international making his debut for his new side during Saturday's 2-1 defeat at the Emirates.