Leading Seaman Faye Turney has told how she feared her Iranian captors were measuring her for a coffin before killing her.
Faye Turney has reportedly struck a deal worth more than £100,000
The only woman among the 15-strong crew told the Sun her captors asked how she felt about dying for her government and never seeing her daughter again.
She is said to have received a six-figure sum for the interview.
Relatives of soldiers killed in Iraq have criticised the decision allowing the navy crew to sell their stories.
Leading Seaman Turney, known as Topsy, said her lowest moment came when her captors isolated her from her colleagues and told her they had been sent home.
"All I could think of was how completely alone I was. They could do anything now and nobody would know," she told the Sun.
She says the Iranians used psychological pressure to force her to "confess" that she and her 14 colleagues had strayed into Iranian waters.
Leading Seaman Turney also spoke of her fears after hearing wood being cut near her cell, followed by a woman measuring her body with a tape.
"She shouted the measurements to a man outside. I was convinced they were making my coffin," she told the paper.
The newspaper reported that she was kept in a tiny room measuring 6ft by 5ft 8ins and asked how she felt about "dying for her government".
She said she feared everyone in Britain would "hate" her, but wanted to be home for her daughter's birthday next month.
Leading Seaman Turney has also given an interview to ITV1's Tonight with Trevor McDonald programme, to be shown on Monday.
Meanwhile Arthur Batchelor, 20, the youngest of the British sailors to be held captive, told the Daily Mirror about his "nightmare" at the hands of his captors and how he "cried like a baby" in his cell.
He said Leading Seaman Turney risked beatings from guards for whispering reassurances to him as he sat petrified and blindfolded on a boat after they were captured at sea.
He told the newspaper: "A guard kept flicking my neck with his index finger and thumb. I thought the worst, we've all seen the videos. I was frozen in terror and just stared into the darkness of my blindfold."
The interviews came as Iran released more video of the sailors, showing them socialising and relaxing during their captivity.
Iran's state-run Arabic satellite TV channel Al-Alam showed several of the sailors and marines eating at a long dining table, watching football on television and playing table tennis and chess.
Iranian television released video showing the sailors relaxing
The images contrasted sharply with the crew's description of their ordeal, which they say included intimidation and isolation.
Both of the officers among the captives have said they do not plan to profit from the story.
Royal Navy Lt Felix Carman said any fee was likely to go to charity.
"I am not interested in making money out of this," the 26-year-old from Swansea told the BBC.
"My main aim is to tell the story. There's some people who might be making money, but that's an individual's decision, that's very private."
Meanwhile, Captain Chris Air said that he did not plan to sell his story but insisted his fellow service personnel had the right to.
The Royal Marine told ITV Granada News: "I think it can be part of the process to get things off their mind. To be honest, it didn't seem that traumatic at the time to me and I don't think it's going to affect me in a terrible way."
The MoD said its decision would ensure officials "had sight" of what might be said as well ensuring "proper media support" to the captured crew members.
Sally Veck, whose 19-year-old daughter Eleanor Dlugosz, a medic, was killed in Iraq criticised the MoD for letting the sailors and marines profit from their ordeal.
She told the Times: "If you are a member of the military, it is your duty to serve your country.
"You should do your duty and not expect to make money by selling stories."
The sailors and Royal Marines were held after Iran accused them of entering its waters, a claim they denied.
The MoD has said experiences of the navy crew amounted to "exceptional circumstances" that allowed its usual ban on such payments to be lifted.
PR agent Max Clifford said he had been approached by the fathers of two of the crew and had advised them to give the money to families of those who had lost their lives in Iraq to defuse any "backlash".