Fully-vaccinated passengers will have to buy lateral flow tests on arrival in the Bailiwick of Guernsey from 3 August.
The tests will be offered to those vaccinated within the Common Travel Area who have received their second dose more than 14 days prior to travel.
Passengers will have to pay £25 for a pack of five tests, the Civil Contingencies Authority (CCA) said.
Tourists are additionally being encouraged to take a pre-travel test.
The announcement comes after plans to require proof of a negative Covid-19 test for fully vaccinated people arriving into the Bailiwick of Guernsey were “put on hold” by the CCA.
The latest rules will ask full-vaccinated travellers to take the lateral flow test every other day for nine days.
‘Protect our community’
The decision excludes passengers from Jersey, who will still need to show proof a negative PCR test taken within the 48 hours before travel.
Children aged 11 and under travelling with a full-vaccinated passenger will not be given a test pack.
Young people between 12 and 17 will continue to receive a PCR test on arrival and on day seven, the CCA said.
Adults will need to pay for the tests when completing the Travel Tracker process.
Others travellers – those not fully vaccinated or those who start their journeys outside the Common Travel Area – are subject to a test and isolate system based on the level of Covid in the places they have come from.
Deputy Peter Ferbrache, Chairman of the CCA, said the decision “seeks to provide an additional level of mitigation to help further protect our community without significantly impacting those who are fully vaccinated and want to travel”.
He said: “Paying for the test will be a condition of travelling into the Bailiwick and therefore compulsory.”