Updated Package Travel Regulations will give protection to an extra 10 million holidays a year, according to the Government.
But ABTA is reminding customers the extended protection only applied to bookings made from July 1 2018, when the updated regulations came into force.
PTR 2018 has been updated in response to the growing number of people who book individual components online, but also applies to those booking separate elements in a high-street agency – as long as they pay for them all together.
ABTA chief executive Mark Tanzer said: "Under the new regulations more holiday travel arrangements will be classified as packages, which offers the best form of protection for customers."
He added: "While the number of holidays financially protected isn’t expected to significantly increase under the new regulations – the level of protection will, as they will also be required to have legal protection.
"Whether a trip is covered by these regulations or not will depend on what is booked and how it is booked, so it is very important to check with the travel company at the time of booking.
"It’s also important to remember that these regulations apply to holidays booked on or after 1 July, holidays booked before then will be covered by existing regulations."
Which? travel editor Rory Boland said: "Package holiday regulations have finally been dragged out of the dark ages.
"These new rules mean far more holidays will be classed as packages, giving holidaymakers protection when something goes wrong."
