Cardiff “can cope” with the 170,000 people expected to pour into the city for the Champions League Final, organisers have said.
It will become the smallest city to host the final when Juventus play Gareth Bale’s Real Madrid on Saturday.
And Cardiff will be “at capacity”, the Football Association of Wales (FAW) has said.
But Alan Hamer, who heads its organising committee, said the Welsh capital can “absorb” the influx.
Authorities have already said the final – the world’s biggest club football match – will mean Cardiff will be at its “busiest ever” in 2017’s single largest sporting event.
Mr Hamer said the scale of occasion had been the “biggest challenge” for the FAW, its lead organiser.
“When you look at cities the size of London and Berlin, [with] big footprints, we’re pretty much taking every parcel of land in Cardiff.
“So, the size has been a challenge, but it’s also an advantage because when people do come, they can walk around pretty easily.
“I think that will put Cardiff on the map and make it different to other finals.”
The match will be the biggest sporting event ever staged in Wales, with a live global TV audience of 200 million and security arrangements on a similar level to the 2014 Nato summit in Wales.
But Mr Hamer said the massive number of visitors is not unprecedented.
“It’s been done before. I think when Wales played Ireland in the 2005 Grand Slam [rugby] game They said about 250,000 people were in the city,” he said.
“We know the city can cope.”
The women’s Champions League final will be held on Thursday at Cardiff City Stadium at 19:45 BST, with the men’s final at the same time two days later at the re-named National Stadium of Wales.
The latter will be open on Saturday from 11:00 to 17:00 on Saturday.
Unlike during last summer’s Euro 2016 championship, Cardiff will not host a fanzone where the match can be watched on a large screen.
Mr Hamer said the organisers had spoken to the police and decided against it.
“We would have loved to have been able to put a public screen in but the problem we faced is the city is already going to be at capacity.
“If we had put a free-of-charge, public screen in the city – particularly now that Real Madrid [and] Gareth Bale [are in the final] – we would have so many people coming in from local areas. The city would basically become gridlocked.”
Mr Hamer said no other Champions League final host city had ever installed a free-of-charge public screen for the match.
“Attracting lots of ticketless fans can be a big problem. We’re maxed out on accommodation, on transport.
“There are lots of bars in Cardiff – it’s unique. There’s lots of places that people can watch the game. We would urge people to watch it in their local clubs as well.”
On Friday, the FAW announced the stadium’s roof would be closed for safety reasons during the final.
‘Now’s the time’
It said the security operation for the four-day period, from 1 to 4 June, will be the “biggest ever seen” for a sporting event in the UK.
Police have said there will be a “ring of steel” around the event with significant road closures.
Mr Hamer said he wanted fans to be “reassured” the city would be safe and urged local people to take advantage of the event.
“The best footballers in the world are on our doorstep and these opportunities don’t come around very often so people shouldn’t be complacent and think ‘well, we’ll see them next time’.
“Who knows? There might not be a next time, so now’s the time to get involved in the event,” he said.