While stock markets are expected to react negatively to a “leave” vote, Britain’s exit from the European Union could also affect the plans of Canadian travellers who were hoping to visit the U.K. – or anywhere in Europe this summer.

Some travel sites have already seen a decline in the number of searches for flights from Canada to the U.K. since the referendum was first announced in February.

Cheapflights.ca, for example, has had an average six per cent weekly decline in searches during March, April and May, according to the site’s managing director, Andrew Shelton.

“We see this as less a case of Canadians falling out of love with destinations on that side of the pond, and more that they’re choosing to wait and see the result of the vote,” he told BNN in an email.

Another popular travel site, Expedia.ca, has seen consistently strong growth for standalone flights from Canada to the U.K. year-over-year, but has noticed a slowdown in bookings over the past week, according to Expedia Canada’s brand marketing director, Adam Francis.

“While Expedia.ca has noticed a slowdown for U.K. flight bookings over the past week compared to the previous 28 days, Expedia.ca cannot attribute or pinpoint this to the recent Brexit news,” Francis told BNN in a written statement.

A vote to leave could also impact the value of currencies, including the Canadian dollar, according to Alfonso Esparza, senior market analyst at Oanda. The uncertainty around the vote alone has caused currencies to react.

“No one really knows what's going to happen if Britain really does leave and that means that they [investors] are flocking to the stronger currency,” he told BNN in an interview.

“So we see the [U.S.] dollar rising, we see the yen and the Swiss Franc rising. And the Canadian dollar is losing those flows because people are preferring currencies other than the Canadian dollar.”

Shelton echoed Esparza’s sentiments and said that the effects of Thursday's outcome -- everything from the cost of foreign exchange rates to flight prices -- is almost impossible to predict.

“The only certainty in the event of a ‘leave’ vote is that those in the travel industry across Europe will be working hard to protect what is an extremely valuable and established tourism market to and from the U.K.,” he said.

So picking the perfect time to book that flight or purchase your foreign cash may be tricky.

Britain will decide whether to stay or remain in the European Union on June 23. And as the referendum approaches, there has been widespread speculation on how a vote to leave might impact the global economy.

The euro, the British pound and the Canadian dollar were all down last week due to worries about a possible Brexit, but were up so far this week after weekend polls suggested that more Britons were in favour of staying with the EU than leaving it.

The U.K. is one of the most popular destinations that Canadians travel to. About 740,000 Canadian residents visited the U.K. in 2013, a six per cent increase from the previous year, according to the World Tourism Organization.

A report from cheapflights.ca released last month revealed that London, U.K. was the fifth most searched travel destination for Canadians between May 1, 2015, to April 30, 2016.