Derry O'Rourke (56) from Edenderry, Co Offaly, was given 10 years on two charges of rape and four years on four different sample indecent assault charges in relation to one girl between 1975 and 1978.
Justice Paul Carney said he had to take into account "the horrific nature of the crime." He added that the victim was groomed for the purpose of that abuse.
However, the sentences will run concurrently from March 2000 so Mr O'Rourke will be out in the same time period.
Mr O'Rourke was first jailed for 12 years in 1998 after he pleaded guilty to 29 charges relating to offences involving 11 girls. His 12-year sentence shocked the sport and led to the introduction of strict new child-protection measures.
In 2000 he was then given a further four-year sentence after he pleaded guilty to more charges of indecently assaulting young swimmers between 1970 and 1992.
The youngest victim was 10 years of age and they were all being coached by him.
Speaking afterward, the victim involved in today's ruling, who was 13 at the time the assaults began, said she was not going to give him any more of her time.
The victim told the Central Criminal Court that she has been trying to ease the pain ever since. The woman, who was being coached by Mr O'Rourke as she attended a Dublin boarding school in the 1970s, said: "This has devastated every aspect of my life."
She said she was thankful to the first girls who had the courage to come forward.
The court heard that after Mr O'Rourke was sentenced in 1998, she saw his picture in the paper and was able to acknowledge what had happened for the first time.
As Mr O'Rourke sat to her right-hand side, she said: "I am not that innocent, trusting, willing and enthusiastic little girl who did everything you asked me to."
She said she was pleased to be able to stand there and not be frightened of him.