Shopping was the next most popular answer in the survey, carried out last month by researchers from Nottingham University Business School.
On a scale of zero to 10, Robin scored an average of 8.2 for visitors and 8.6 for locals in terms of the importance of his links to the city and most agreed he was a "hero".
Yet tourism experts say neither Nottinghamshire nor Yorkshire, which stakes a rival claim to the legend, has made the most of Robin despite fighting over his origins.
In fact, five years ago Nottingham infamously ditched him from its branding in favour of a controversial "slanty N" logo designed at a cost of more than £100,000.
Study co-author Anita Fernandez Young, a lecturer in tourism management and marketing, said: "What we have in the case of Robin Hood is a brand without a product. We should recognise that Robin's name is known worldwide. Everyone is aware of the basic story and at least some of the characters and locations involved.
"And yet in Nottingham and Nottinghamshire the places with which he's most widely associated Robin seems to disappear a little more each year.
"He's the archetype of a hugely valuable cultural icon going to waste. It's as if we're so focused on embracing the modern that we're afraid to make the most of the past."
Robin made headlines around the world when Yorkshire's challenge to Nottinghamshire's claim went all the way to the Houses of Parliament in 2004.
David Hinchcliffe, the then MP for Wakefield, tabled a Commons motion citing "the lack of any factual basis" to Nottinghamshire's alleged links.
Research co-author Liz Crosland-Taylor said some people seemed reluctant to name a mythical figure as their "top of mind" image for Nottingham.
It could therefore be likely that the "Robin Hood effect" might be even higher than found in the study, she claimed.
She said: "Even though Robin is mythical, the focus group part of our research indicated visitors and locals alike expect to see visitor product aligned to the Robin Hood theme. The fact that Robin is a legend means the story and product can be constantly updated to maintain consumer interest.
"The news of the House of Commons challenge appeared all over the world. That gives us a very rough idea of the potential we're failing to tap.
"While our research showed a high level of satisfaction with the Nottingham experience, many visitors were disappointed with the Robin Hood dimension."
The DeHaan Institute, the School's tourism and travel research facility, carried out the study, collecting data from 185 visitors to Nottingham and 200 locals.
The research discovered 10 per cent of regional, 43 per cent of other UK and 70 per cent of international visitors were making their first trip to the city in at least a year.
Some 87 per cent of regional, 69 per cent of other UK and 50 per cent of international visitors said they were likely to return to the city within 12 months.
Professor Leo Jago, the Institute's Acting Director, said: "The fact that visitors and locals were united in associating Robin Hood with Nottingham shows his enduring value.
"As a recent arrival to the UK myself, I'm not surprised at the importance of Robin Hood for the city in the minds of international visitors. But I was taken aback that he was more frequently mentioned by locals than shopping and other activities.
"The city still almost unwittingly acknowledges his worth even in the form of various street names but our findings suggest there's so much more to be made of it.
"Now that we've seen the importance of Robin to the Nottingham brand, we're in the process of estimating his actual economic value to the city."
Explore further: Poll shows giant gap between what public, scientists think