People arriving in the Bailiwick from the North West or South East of England now face longer isolation periods.
NW England as become Category 4 - meaning quarantine until a negative Day 13 coronavirus test.
SE England now Category 3 and demands self-isolation until a negative Day 7 test.
Both regions were upgraded at midnight (9 June) and concerns about coronavirus rates and variants.
They had been on watchlists for a week, giving passengers notice of an imminent change in their status.
Southampton Airport, Poole and Portsmouth Harbour continue to be treated as Category 2 for transiting passengers - providing they have only passed through the ports and have not been out into the wider region/town.
Other changes that have come into force this week include East Scotland being added to the Category 3 watchlist, and Italy and the United States becoming Category 3 countries.
The Civil Contingencies Authority is expected to give a media briefing at 1pm on Friday (11 June)
Speaking last week, the Chief Minister Deputy Peter Ferbrache said the Bailiwick remained on track to ease border restrictions from 1 July, but that the changes were 'under review'.
Three comedians added to Guernsey Literary Festival line-up
Guernsey's hospital moving away from laughing gas anaesthesia
Guernsey hosts global Indoor Bowls competition
Guernsey rugby player selected for Scotland under 17s