The man and woman were allegedly set upon at around 3.45am on April 5 after enjoying a night out at the Blue Fly Cafe Bar on New Street.
It is alleged that one of the suspects repeatedly punched and kicked the 24-year-old man, over a period of 10 minutes, while his girlfriend, 29, was repeatedly pushed to the ground.
The sustained assault only came to an end when a passing taxi driver came to the couple’s aid.
The male victim suffered serious injuries including a broken jaw, chipped teeth and bruising. He received emergency treatment at York District Hospital.
North Yorkshire Police said the five men seemingly targeted the couple because they are from another country.
The suspects were described as white, aged between 20 and 25, short or shaved hair and spoke with English accents.
One of the men was about 5ft 7in tall, had short or shaved brown hair, and was wearing a short-sleeved, light-coloured t-shirt with trousers.
Pc Sophie Wilson, of the York Safer Neighbourhood Team, said: “This is a very disturbing incident which will quite rightly shock the local community in York and those who regard the city as a friendly and safe place to visit.
“We are doing everything we can investigate this case and bring those responsible to justice. We are also providing support to the young couple from Spain who have had their stay tarnished in the most sickening and vicious way.”
As well as a general appeal for witnesses, the police are trying to trace the taxi driver.
Pc Wilson added that the victims were “extremely grateful” the driver had the decency to stop and help.
Anyone with information is asked to call 101 and ask for Sophie Wilson, email [email protected], or call Crimestoppers anonymously on 0800 555 111.
The attack comes just one month after York was voted the world’s safest city for short-break tourists.
From Post Office Travel Insurance, the survey of 2,075 UK adults showed that 72% felt York was safe with only 1% considering the Yorkshire city risky, and 26% having no view.
Of the 42 cities asked about Cairo was listed the least safe, with 56% seeing the Egyptian city as risky and only 7% saying it was safe.