The Which? experts say one common trick is for scammers to claim a credit card payment has not gone through and then ask for a bank transfer instead.
Which? references a MailOnline Travel report from earlier this year that highlighted how fake ski chalet websites have been plaguing holidaymakers.
Several outraged skiers told MailOnline how they thought they'd booked a luxury chalet, but actually wired money to scammers – with one victim losing 30,000 euros. They then discovered the banks were powerless to do anything about it.
The sites took pictures from real ski chalet sites and offered them under different names at vastly reduced rates.
When customers made a bank transfer payment, the thieves disappeared with the money.
In order to protect yourself, the consumer champion advises checking the reliability of the property by doing a Google image search of pictures of the property to see if they show up on other websites.
Which? also says that travellers can use Google Maps and Street View to see if a property actually exists at the address.
It also advises to never pay by bank transfer and insist on paying by credit card instead. If you pay by credit card, you have the protection of Section 75 of the 1974 Consumer Credit Act. This means that you can claim against the card provider if you are ripped off.
Dodgy flight deals
Rock bottom prices on flights are often offered on what appear to be convincing websites that have been set up by fraudsters.
Which? reports that Action Fraud says that a recent wave of scams have been targeting travellers heading to Asia, Africa and the Middle East.
The consumer group says the scammers choose trips that seem "once in a lifetime" and in some cases buy genuine flights with stolen credit cards.
However, once the card is reported stolen, the flight is cancelled by the airline but the fraudsters still have bogus confirmation reference numbers that they then sell on to unsuspecting victims.
Which? says the best way to avoid being scammed on airfares is to make sure you book through an agent that is a member of Abta.
Document deception
The internet is full of fake websites that are charging over-the-odds for travel documentation - that sometimes isn't legitimate.
Which? reports that recently, dozens of British holidaymakers were forced to buy visas on arrival in Turkey as the ones they had were purchased from a fake website.
Another scam the experts warn of is websites charging Brits for a European Health Insurance card (EHIC), when they are actually completely free.
Meanwhile Which? says that half of the top 20 search results for 'Esta visa' for the United States were unofficial. It's available for $14 direct from the US government's own site (esta.cbp.dhs.gov).
The consumer group says that heading to the Foreign Office website is the best way to find the official website for visas.
Meanwhile to get an EHIC, visit the official website
Wi-Fi woes
Logging into the free Wi-Fi is often one of the first things travellers do when they arrive at an airport .
But fraudsters are known to be able to hack into Wi-Fi connections to steal personal data.
Which? says some even convince holidaymakers to provide credit card details so they can steal more than browsing habits.
The experts say to avoid being duped, it is advisable to ask airport staff for the real Wi-Fi connection to make sure it is legitimate.
It also says that any connection that doesn't ask for a password straight away should also be treated with extreme care.
Meanwhile if you are asked for IDs and passwords, always provide fake details.
'Free' holidays
Thousands of people have been pressure-sold timeshare accommodation.
But Which? says the trick has now evolved with scammers offering the victims scratchcards where they 'win' free holidays and are then pressured into buying timeshares.
The consumer group points out that although timeshares aren't illegal, many people have been left with property they don't want after paying high fees.
The experts advise that people should never accept 'free holidays' and ignore any hard-sell techniques.
It also suggests that timeshare owners should beware of companies who say they can sell it on for you but demand money upfront.
Fake tickets
Major sporting events and concerts provide another windfall for fake websites and scammers.
Which? says that just this summer there were reports of World Cup tickets being sold for £23,000 per pair with no guarantee the buyers would be allowed in the stadium.
Similar scams have also been carried out on music fans willing to pay huge sums of money to see popstars such as Justin Bieber.
Which? explains that criminals often exploit events where prices are high and availability is low.
In order to not get sucked in, Which? advises only buying tickets from legitimate sites and from web pages that have the padlock symbol in the corner by the URL and start with 'https'.
For those who do buy second hand tickets, the experts say that they should make sure resale is allowed as some tickets are for the named person only.
Resellers are also legally required to tell buyers the original face value of the ticket and where they will be sitting.
Members of Star (Society of Ticket Agents and Retailers) have signed up to a code of conduct and have a procedure for dealing with complaints.
Which? Travel editor Rory Boland told MailOnline Travel: 'Criminals are finding ever more sophisticated ways to dupe holidaymakers, both in the booking process and when they're on the holiday itself.
"If something seems too good to be true, it almost certainly is. Don't hand your money over until you can be sure it's the real deal."
