A Notre Dame pupil who has not left the island in the last 14 days has tested positive for Covid-19.
The first case of community seeding since the end of the Bailiwick's second lockdown in March has been identified in Guernsey.
A Year 6 child tested positive yesterday (20 July) and has no known links to positive cases. Contact tracing is underway.
The child became symptomatic after the last day of term.
Director of Public Health Dr Nicola Brink says the island is well prepared.
"Instances of community seeding are to be expected as we adjust to living with COVID but our robust contact tracing measures along with our high vaccination rate means we are well placed to minimise onward transmission.
"It is worth noting that all schools have had additional safety measures in place since the start of the pandemic, including hand sanitising on entry and general good hygiene. We are incredibly grateful to all teaching staff and children across our schools for having adhered to this so responsibly."
End of term activities means that some years groups have been mixing.
All Year 3, 4, 5 and 6 pupils at the school will be tested. Pupils in those year groups are being asked to self-isolate until they have received a negative test result.
Parents and other household members do not need to self-isolate at present.
Anyone linked to the school that has not heard from Public Health, should carry on as normal, while continuing with good hygiene measures that are now common practice across the community.