Guernsey will accept a negative lateral flow test (LFT) for fully vaccinated Jersey arrivals from Tuesday 3 August.
This replaces the requirement for double jabbed passengers to have a negative PCR test result - although they will still be accepted.
The LFT must done under supervision within 48 hours before travel.
Guernsey's government understands that observed tests can be obtained through some Jersey pharmacies.
They will also accept tests which are supervised online, providing an email or text confirmation is given.
Fully vaccinated travellers from Jersey will also have to buy a pack of five lateral flow tests to use on arrival - in line with other double jabbed visitors from the Common Travel Area.
These kits were due to be brought in from Tuesday 3 August but their rollout has been delayed because of supply issues.
Once available, these self-tests should be done as soon as the traveller arrives home or at their accommodation and then on every other day.
Meanwhile, anyone travelling from Guernsey to Jersey for less than 48 hours will still need a PCR test when returning back into the Bailiwick.
There will be no change to pre-travel testing for people who have spent time in Jersey during the 14 days of their arrival into Guernsey, but this is being kept under review.