The Spanish players have put pen to paper on five-year contracts with the Valencian outfit.
A statement from Villarreal read: “Villarreal and Malaga have reached an agreement for the transfer of players Samuel Garcia and Samuel Castillejo, who will play during the next five seasons at the Yellow Submarine club.”
Garcia, a 24-year-old striker, and 20-year-old winger Castillejo, shone for Malaga this season, helping the Andalusian club finish ninth in the Primera Division.
Castillejo made 34 league appearances, scoring one goal and setting up five more while Garcia hit the back of the net five times in 38 games.
“I’m really enthusiastic about this new stage of my career,” Garcia said on his club’s official website. “Villarreal is the perfect place to keep developing as a player.”
Castillejo was also thrilled to have joined Villarreal, who play in the Europa League next season.
“I feel really grateful to Villarreal for this great opportunity that they have given me and I hope I can make the most of it.
“This is a great club that counts on youngsters and I want to repay that confidence.”
Villarreal, coached by Marcelino, also strengthened their defensive line by bringing French goalkeeper Alphonse Areola on a season-long loan from Paris Saint-Germain.
The 22-year-old spent this campaign on loan at Bastia, making 40 appearances for the Ligue 1 club.
Villarreal were keen to acquire a goalkeeper with their current number one Sergio Asenjo out of action with a serious knee injury.
“I know the situation and of Asenjo’s long absence through injury and I’m here to help out,” Areola said. “I also want to continue to grow as a player.
“This is a great club, with history in Europe.
“This experience will allow me to play in the Primera Division, a league that has the best players in the world, while I will also be able to play in the Europa League.
“I had no hesitation when offered the chance to come to Villarreal.
“This is a great opportunity that I cannot miss.”