A man and a woman were each fined £10,000 ($13,924) for failing to go into hotel quarantine after returning to the UK from Dubai.
Officers said on Tuesday that the pair, from Wirral in north-west England, entered the UK from a third country in an attempt to avoid the mandatory 10-day quarantine.
The hotel quarantine policy applies to travellers from a so-called red list of 33 countries, which includes the UAE.
Travellers from those countries must declare if they have been to a high-risk country in the 10 days before arriving in the UK. From Monday, international travellers will also have to carry a form to prove they are allowed to travel.
Officers said they received a report about the pair last Tuesday before the two were fined the maximum penalty on Friday.
They were subsequently transferred to a quarantine hotel.
Chief Inspector Chris Barnes, from Merseyside Police, criticised the pair for their "selfish, inconsiderate, and potentially dangerous" actions, reminding travellers from red-list countries that they need to enter the UK through specific ports of entry.
“In this instance, the pair in question avoided a direct flight route back from Dubai to one of the specified airports in an attempt to evade this process," he said.
"However, this was ultimately unsuccessful and has now resulted in a significant fine of £10,000 each.
“I hope this incident sends out a clear message to anyone considering breaching travel regulations in this way that we will not tolerate it, and you will be dealt with robustly," Insp Barnes said.
"We are at a crucial point in the pandemic and it’s vital that everyone continues to abide by the restrictions so that we can meet the criteria needed for lockdown to ease. By not doing so, you are not only jeopardising this process, but recklessly putting your health and the health of others at risk.”
Travellers who stay in quarantine hotels are forced to pay at least £1,750 for 11 nights, rising by an extra £1,200 if they test positive for coronavirus and need to extend their stay.
The scheme – designed to keep out mutant variants of the virus – was widely criticised, with some travellers holding up signs to the media to complain of human rights breaches.
Last week, one passenger held up a sign that read "HM Prison Heathrow", while other home-made signs read “What a way to spend your birthday”, and “Next time I’m coming home in a dinghy via Dover”.
Others summed up the experience with a thumbs-down to photographers outside the hotel.
One couple, Wagner and Elaine Araujo, told The National that the first few days were horrible but that they had become used to it and decided to make the most of the time.
"It's been like a second honeymoon," said Mr Aroujo, who comes from Brazil but has lived in London for 20 years.
“It’s like coming out of prison. We have a taste of freedom. It feels amazing,” Mrs Aroujo said.