See "Bolsa de Aventuras para Spectrum en Espanol" at http://www.speccy.org/base/ for an attempt to collect all Spanish text adventures for the Spectrum ever released.
Achus Babilonia, by Penazo Soft.
La Aventura Espacial (the Space Adventure), by Aventuras AD. (An Amstrad version of this game is in games/amstrad/spanish/espacial.zip, a C64 version is in games/c64/spanish/espacial.zip, and a DOS version is in games/pc/spanish/espacial.exe, and an MSX version is in games/msx/spanish/AventuraEspacial.zip)
Chichen Itza; book three (in two parts) of the trilogy Leyendas de Ci-U-Than, an illustrated text adventure by Aventuras AD. (An Amiga version of this game is in games/amiga/spanish/chichen.zip, and a DOS version is in games/pc/spanish/chichen.exe)
Disappearance! (Henry Holmes #1), by Juan Manuel Martin Castillo.
Dr. van Halen: Último Acto. Created by Josep Coleta using PAWS.
Freeze Aliens, by Juan Manuel Martin Castillo.
El Jabato, an illustrated Spanish text adventure by Manuel Gonzalez, Paco Zarco, Juan Antonio Darder and Carlos Marques. (An Amiga version of this game is in games/amiga/spanish/jabato.zip, an Amstrad version is in games/amstrad/spanish/jabato.zip, an Atari ST version is in games/atari-ST/spanish/jabato.exe, a C64 version is in games/c64/spanish/jabato.zip, and a DOS version is in games/pc/spanish/jabato.exe, and an MSX version is in games/msx/spanish/Jabato.zip)
La Aventura Original, an illustrated text adventure by Andres Samudio, Manuel Gonzalez, and Carlos Marques, based on Colossal Cave. (An Amiga version of this game is in games/amiga/spanish/original.zip, and a DOS version is in games/pc/spanish/original.exe, and an MSX version is in games/msx/spanish/AventuraOriginal.zip)
Tulum y Coba: Los Templos Sagrados; book two (in two parts) of the trilogy Leyendas de Ci-U-Than, by Aventuras AD. (An Atari ST version of this game is in games/atari-ST/spanish/templos.exe, and a DOS version is in games/pc/spanish/templos.exe)
Historias de Medialand, by Javier San Jose.
Memorias de un Hobbit, by Javier San Jose.
El Sueno Profundo (part 1), by Juan Manuel Martin Castillo.
Strange Tale (Henry Holmes #2), by Juan Manuel Martin Castillo.
The House, by Juan Manuel Martin Castillo.
Things!, by Juan Manuel Martin Castillo.
Whitman Day (parts 1 to 3), by Juan Manuel Martin Castillo.