They intercepted enemy communications to gather the Nazi Enigma machine codes which British code-breakers could then work on.
These secret listeners, frequently risked their lives to gather messages from the Germans and Japanese.
Their information was crucial to staying one step ahead of the enemy, and a new book 'Bletchley Park’s Secret Source' hopes to raise the profile of these remarkable women.
Pat Davies was a former WRENS Secret Interceptor.
Speaking to Forces News, she said: "They had Y stations and I would be listening to German ships and shore bases and writing their messages down and that was what we did.
"We had watches of so many hours on, so many off, right around the clock.
"If it was plain language you sent it on at once by phone to the nearest Naval intelligence centre.
"If it was four-letter Enigma code it went by teleprinter to what we knew as Station X, which was Bletchley Park."
It is her story and the work of the other women interceptors of Y Service that inspired the book.
She continued: "We did know it was important because, obviously, we were told we must, particularly with codes, get it down as exactly as we possibly could.
"You often got interference and fading and so it was often quite hard work getting it accurately written down, but we did.
"What they actually did with our messages, we didn't know because it was very much one way, but we did realise that it mattered, that it was really important, and might even save lives."
Author and former Navy Captain Peter Hore is the first to have written a book revealing the work of the wireless interceptors.
He said that "until today there has been no history of the WRENS and the Y Service".
"I have tried to show in this book that they weren't just backroom girls, they were exposed to danger.
"They were shelled... they were bombed, they worked under the flight path of V1 and V2 bombers.
"In three tragic cases, when they were at sea on their way to and from overseas stations, they were torpedoed," he added.