Eleven men - two posthumously - were given the Légion d'Honneur at a ceremony on the navy helicopter carrier Dixmude at HM Naval Base Devonport.
They fought at the D-Day Landings more than 70 years ago.
Plymouth's honorary French consul said the event on board the warship was "quite exceptional" and would never be repeated.
It was the second time France had held such a presentation on a warship, with a similar ceremony staged on board FS Aquitaine in Glasgow in 2015.
The men who were honoured at Sunday's ceremony are aged between 90 and 97 years old.
Gillian Garrlick collected the medal on behalf of her late father, Charles Dixon, from Plymouth.
"My father had actually received it through the post back in October, so he did know he'd received it but was waiting for an official presentation.
"Unfortunately he died on 30th December so didn't get to be here today, but it was an honour to receive it for him."
D-Day veterans have received France's highest military decoration on a French warship in Plymouth.