Levin woman Heather Robinson was happy to produce documentation to dispel any doubts about her age when asked "can I see your licence please, madam".
The 90 year old swam 90 lengths of the Levin Aquatic Centre for her birthday on Friday - no mean feat - two years after swimming 88 lengths of the poll on her 88th birthday.
"I didn't do it last year because I was ill," she said.
Mrs Robinson managed to achieve the feat in less than two hours, a good effort considering she was not as fast as she once was, by her own admission.
"I've lost my kick now so it's really just my arms, but we get there," she said.