The Argentine attacker is widely regarded as one of the country’s most promising youngsters, having been compared to Barcelona star Lionel Messi and Atletico Madrid's Sergio Agüero.
Almería had been following the player for quite some time now, and although Piatti arrives at Estadio del Mediterráneo for an undisclosed fee, it is believed that Estudiantes de La Plata will keep 25% of the player's registration.
Piatti has signed a seven-year deal, with the Spanish side stating that they hope the Argentine will be one of La Liga’s new sensations.
The Andalusian club, who managed a respectable eighth-place finish in La Liga, claim that they deflected interest from Juventus and Manchester City to sign the Argentine prospect.
Piatti was part of Estudiantes squad that lifted the 2006 Apertura trophy and the Argentina Under-20 squad that won the FIFA U-20 World Cup last year.