The 86-year-old rest-home resident was found in a distressed state in Severn St, opposite the Oamaru Police Station, yesterday morning.
It appeared the trio, who were all in their 80s and on holiday, had travelled from Timaru in the morning and stopped at the public toilets.
When the woman came out of the toilets, the car, driven by the male friend, had gone.
"They forgot her. They assumed she was in the back seat," Senior Constable Bruce Dow said.
Police sat with the woman - who did not want to leave the spot - for about an hour and gave her a cup of tea while inquiries were made.
Police also headed north from Dunedin to try to locate the car.
It was not until the two men were at Katiki, just north of Palmerston, that they discovered the woman was missing and they returned to Oamaru.
She spotted the car as soon as it pulled up.
There were some tears shed and it was "quite a nice reunion" before the trio continued on their journey, Snr Const Dow said.
