At the start of the film, set in 1939, the four sisters put up a map of the world to keep track of the soldiers' locations, but the map is contemporary from the year the film was made (1957), showing numerous nations that did not exist in 1939, for example: Laos, Cambodia and Vietnam (which would have been French Indochina in 1939), Indonesia (formerly the Dutch East Indies), Thailand (called Siam in 1939), and Pakistan (which was part of British India), among other countries.
The first time Jean Simmons' character meets Paul Newman's character is in a Wellington, New Zealand restaurant, in 1942 or 1943 (American troops first arrived there in 1942, the war ended in 1945). Newman is reading an early paperback copy of the book "Nine Stories", by J.D. Salinger. The hardback version was published in 1953. The Signet first paperback edition Newman is reading was published in July 1954. The title is very briefly but clearly visible as Newman closes the book and puts it down.
The movie takes place in New Zealand. Toward the end of the movie, one of the sisters and her son are flying away. The registration on the aircraft is SU-AAC. "SU" is the registration letters for aircraft certified in Egypt.