Narciso Ibáñez Serrador wanted Tom and Evelyn to speak English to each other throughout the movie. This would add to Evelyn's communication troubles since she isn't able to speak any Spanish at all. However, since the producers feared that the public would get distracted by the subtitles, they made a last minute decision and had both characters dubbed into Spanish for the original version. Ibáñez Serrador has always been very critical of this decision, he felt that it damaged the atmosphere of the film.
Even though the movie takes place on an island, all the town scenes were filmed in Ciruelos (Toledo), more than 250 miles away from the sea.
The script was written in only four days.
Despite his prominent career, this is the second and last feature movie for Narciso Ibáñez Serrador after La residencia (1969).