Christopher Metcalfe, 70, from Blidworth, Nottinghamshire, is accused of five sex offences against three girls in the 1970s and 1980s.
At Derby Crown Court he said he remembered swimming trips but insisted no inappropriate touching took place.
Mr Metcalfe said one girl went to his home but only on a simple errand.
The trial had earlier heard accusations that, as a newly qualified teacher in the late 1970s, he sexually touched a nine-year-old girl during "story-time" and again after a swimming lesson.
Mr Metcalfe is also charged with indecently assaulting another girl at around the same time, when she was aged nine or 10.
A teenage girl, who was in care at Skegby Hall, Mansfield, where Mr Metcalfe was a rural studies teacher in the 1980s, said he raped her in his front room.
But he told the jury the offences "simply didn't happen" and the trip to his house was just to drop off his dogs.
He confirmed pupils came to his farm to see animals but said they were always accompanied by parents.
Under cross-examination, he insisted he had initially told police he "wasn't aware" of whether he had kissed a girl in a shower as he was "in shock" at being arrested.
The trial continues.
An ex-teacher accused of sex assaults on children as young as nine at his home and during swimming trips said the attacks "simply didn't happen".