Flight bookings to the UK jumped since June, driven by the sharp fall in the pound following the vote to leave the European Union.
Overall, there were 4.3% more flights booked to the UK in the 28 days following the vote than last year.
Bookings from Hong Kong leapt by 30.1%, while they were up by 9.2% from the US and 5% from Europe.
Travel researcher ForwardKeys said Brexit had had an "immediate, positive impact" on tourism to the UK.
The organisation, which analyses 14 million reservation transactions a day to monitor future travel patterns, said: "The most favourable exchange rate in decades is probably the major driver for the uptake in bookings to Britain."
While the pound has fallen about 13% against the dollar since its peak on 23 June, the day of the referendum, it has also fallen about 10% against the euro. A lower pound cuts the cost of a holiday for foreign visitors to the UK.
"In the months ahead our data will show whether this post-Brexit bounce is sustained", said Olivier Jager, ForwardKeys chief executive.
The company said worldwide economic uncertainty, terror attacks in France and Belgium and air traffic disruption also benefitted UK tourism.
Its figures are backed up by evidence from other organisations.
Airline BA reported a rise of a third in the number of US customers searching for flights to the UK on its website between 27 June to 3 July, compared with the same few days last year.
Hotels.com said it had seen hotel searches for UK destinations by Americans increase by 50% year-on-year since the referendum.
However, even prior to the referendum, the number of tourists from abroad had risen.
According to the promotional body VisitBritain, in the first three months of the year trips by international visitors rose by 6% to 7.36 million compared with the same time in 2015.
Last year as a whole was a record year for inbound tourism, with 36.1 million visits, up 5% on 2014.
"With the weakened pound Britain offers good value for money at the moment, particularly for high spending long-haul markets such as China and the USA," said VisitBritain.
Tourism is the UK's seventh biggest export earner and is the third biggest employer.