Alberto played last season for Segunda club Ponferradina, and made 29 appearances as the club finished seventh in Spain's second tier.
Wanderers will hope he can fill the void left in the heart of defence, after the departure of Matthew Spiranovic to China.
Alberto, who can also play in midfield, has made 285 senior appearances in a journeyman career spanning 11 years.
The 31-year-old started his career at Malaga, and has played in La Liga for Getafe, and in the Segunda division for Albacete, Cordoba, and Ponferradina.
He hasn't, however, spent any significant period of time at any of his previous clubs, with each stint limited to only two seasons.
Alberto, described as "cultured", stands at 185cm tall, and has scored 16 goals for his various clubs.
He is Wanderers' third Spanish signing of the off-season, and he will join compatriots Andreu, and Dimas, as well as assistant coach Andres Carrasco.
Wanderers CEO John Tsatsimas said he hopes the quality of the club's foreign recruitment will excite, particularly after a lacklustre domestic season.
“Alberto is a fine defender, has had a very good career in Spain, and like Dimas and Andreu will join the Wanderers with a new challenge in front of him which I am sure he will embrace,” Tsatsimas said.
“We have worked very hard behind the scenes to ensure that our squad will be well prepared for the coming season, and from a recruitment perspective we have a very exciting and hungry group of players preparing for our A-League season and the upcoming FFA Cup.
Alberto will link up with his new team-mates towards the end of the week, which will give coach Tony Popovic plenty of time to integrate the Spaniard into his side ahead of Wanderers' A-League kick off on 8 October against Brisbane Roar.
