Holidaymakers have been subjected to 51 changes in the rules for international travel since the first coronavirus lockdown, leaving travellers "looking over their shoulders".
The travel industry has expressed dismay at the "constant rollercoaster" of alterations and called for regulations to be simplified.
Their complaints came ahead of a review of the government's travel traffic light system, which has left many in the industry feeling delated.
At an update last night seven countries were added to the green list, two to the red and none to the amber.
As well as having to gamble on destinations which could change at tri-weekly reviews, holiday makers are having to contend with testing and quarantine rules for people arriving in England since March last year that have been altered 51 times.
A similar number of changes have occurred in Scotland, Wales and Northern Ireland as the devolved administrations have largely mirrored England's rules.
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Many holidaymakers have been forced to cut trips short and rush home before tougher rules for arrivals from their destination were introduced.
Transport Secretary Grant Shapps was among the thousands of UK holidaymakers caught out when Spain was removed from the travel corridors list after being on it for just 16 days.
The Cabinet minister travelled home early from his family holiday to begin self-isolating.
Mark Tanzer, chief executive of travel trade association Abta, said fears about the status of a destination being changed are "reducing the public's confidence about taking an overseas break".
He acknowledged that "public health must come first", but urged the Government to be "much clearer about the data and rationale behind these decisions".
Derek Jones, boss of luxury travel company Kuoni, said international travel rules are "as changeable as the British weather in August", and the complexities have created "enormous challenges for holiday companies like ours".
He added that customers are desperate to understand "the hoops they need to jump through".
Airlines UK, which represents major carriers, said the limited changes yesterday and onerous testing rules meant travel for Britons was "more expensive, burdensome and uncertain" compared with other nations.
It added: "Too many families are having to look over their shoulders for rule changes, and pay through the nose for tests – with no sign from Government that this will change.
"As has happened across Europe, it's time for a more proportionate system where tests are dropped for the fully vaccinated and from destinations where Covid risks are low, with tougher measures targeted at a small number of high-risk countries."
Whether travellers need to self-isolate on arrival, and what tests must be taken and when, depends on their vaccination status and if they have been in a location on the green, amber or red list.
EasyJet boss Johan Lundgren said: "It is no wonder that consumers in the UK are confused.
"Now is the time for Government to simplify the rules around travel, make green truly green and restriction free, remove expensive and unnecessary testing requirements for the fully vaccinated travelling from amber countries, and put an end to this constant rollercoaster of changes."
Paul Charles, chief executive of travel consultancy The PC Agency, described the number of changes to the travel rules as "absolutely staggering".
He said: "Every time there's a change in the traffic lights or the policy itself, that has a huge impact not just on consumers, but also on the travel sector itself, which has had to go through this turmoil over the last 18 months or so.
"It has been one of the worst Government policies ever."
A Government spokesman said: "Our top priority is to protect public health. Decisions on our traffic light system are kept under regular review and are informed by the latest risk assessment from the Joint Biosecurity Centre and wider public health factors.
"We know this is a challenging time for the travel industry which is why we are providing an unprecedented package of support to protect jobs and businesses."
