The Friends of Penrhos Polish Home have raised £180,000 since forming 18 years ago, but say an ageing membership means it is time to call it a day.
The home, near Pwllheli, Gwynedd, was founded in 1949 on a former RAF base to help exiled Polish war veterans.
Nearly 70 years on, it is still caring for the needs of Polish pensioners.
"It will be a bittersweet night," said the charity's chairwoman, Eryl Williams.
"We've got to know so many of those at Penrhos - it really will be with regret that we are saying goodbye."
In its early days after WW2 the RAF base was a stark home for veterans, housed in wooden huts scattered across the former airfield.
But as the decades rolled past, the vast majority of the huts were dismantled, and today, the home provides both sheltered housing and residential and nursing care.
"It has become part of our community, and it really has been a humbling experience being able to help them," added Mrs Williams.
"But there are no new volunteers coming forward, people have other commitments - life is busy.
"So now is the time to say farewell."
A charity dedicated to helping a Polish care home "village" in north Wales will host its last ever carol concert later.