The 31-year-old will officially become an Eagles player on July 1 when his contract with the Spanish side expires and is Roy Hodgson's first signing ahead of the new Premier League season.
Guaita kept 12 clean sheets for Getafe last season, helping the side finish in eighth place in their first campaign back in the top flight, and started his career at Valencia - making over 100 appearances for Los Che.
Palace have been eyeing a new goalkeeper due to uncertainties surrounding the future of veteran shot-stopper Julian Speroni and first-choice number one Wayne Hennessey. The pair are both out of contract at the end of this month.
Wales international Hennessey has stated that he is keen to secure a new deal in south London but the arrival of Guaita will present him with competition for his starting spot.
Speaking to the club's official website, Crystal Palace chairman Steve Parish said: "We are delighted to sign one of LaLiga's best goalkeepers and pleased that we beat off the competition for his signature.
"We very much look forward to Vicente joining in pre-season training and helping us push on in the Premier League."
After a slow start to the 2017-18 season, Roy Hodgson took charge at Selhurst Park and led the club away from the threat of relegation, with the Eagles ultimately finishing 11th.