The credit card company said restaurants, nightclubs, theatres and tourist attractions all benefited from the increase.
Around £12.7m was spent on Visa cards in restaurants last week, an increase of almost 20% on a year ago, while the amount spent in nightclubs was up by 24% to £2.1m.
Visa card spending on theatres and other ticket sales more than doubled to £5.3m, possibly driven by last-minute deals following reports of a quieter period for the theatre industry and also spending on the Olympics as additional tickets went on sale.
Visa is the only credit or debit card accepted at any London 2012 venues.
Steve Perry, commercial director at Visa Europe, said: "The Games are building a massive feel-good factor, not just for the host nation but for all those visitors currently enjoying all the UK has to offer.
"There was plenty to cheer about in the first full week of the Games as total spending on Visa cards by international visitors reached £457m.
"It would appear that visitors are out celebrating the success of their athletes in some style, with restaurant spending up by almost a fifth and nightclub spending by almost a quarter on this time last year."
Visa, a major sponsor of the Olympic Games, said visitors from the US accounted for 12.7% of the total international spend.