JOIN USThe Press Complaints Commission (PCC) said the Middletons had complained of breaches of privacy over the images from 2006, which were published in print and on newspaper websites.
The Mail on Sunday, the Daily Mail and the Daily Mirror agreed to remove the pictures from their web pages, though the images can be easily found elsewhere on the Internet.
The pictures show the two women on and around a yacht off the Spanish Mediterranean island of Ibiza, swimming, diving and sunbathing.
Their brother James and mother Carole were also shown.They were published following William and Catherine's wedding in April, and chimed with a surge in interest in Pippa Middleton, who was the maid of honour.
The PCC documents show the Middletons complained that pictures had been published of them on a boat, taken five years previously, in a place where they had "a reasonable expectation of privacy".
They also alleged that "the photographs had been obtained after the boat had been followed."
In response, the newspapers said the set of pictures had been published several times since 2006 without complaint.
They also said the boat had not been followed, "arguing that the complainant did not have a reasonable expectation of privacy at the location in which the boat was situated," according to the PCC documents.
Nonetheless, the complaints were resolved when the newspapers removed the photographs from their websites "and agreed not to republish" them, the documents said.
A similar complaint against the now-defunct News of the World newspaper has yet to be resolved, the BBC reported.
The images, which included one of Pippa Middleton removing her bikini top, have been removed from the Rupert Murdoch-owned tabloid's website, the broadcaster said.