PUBLIC Health Wales confirmed this week the numbers of Delta variant have increased to 315.
This is a rise of 131 cases since the last update given on June 10.
This variant is now the dominant strain of new cases of Coronavirus in Wales.
The case numbers are expected to rise further over the coming weeks.
Localised community transmission of the variant is evident, with the majority of new cases not being connected to international travel.
Dr Giri Shankar, Incident Director for the Coronavirus response at Public Health Wales, said: “This is a significant development, but one we have predicted, as we know the Delta variant is easier to catch than the previously dominant Alpha variant.
“It is thought that increased mixing is contributing to transmission and we are concerned at this rise in cases.
“There is much we can do to protect ourselves and others.
“Latest evidence shows that both Pfizer and AstraZeneca vaccines are effective against the Delta variant after two doses and so it’s so important to take up the offer of both vaccines.
“By remaining at least two metres away from everyone else, washing our hands regularly, and wearing a face covering we can keep ourselves and our friends and family safe.
“If you develop any symptoms, you must self-isolate and get a test if you or anyone in your household develop symptoms.”
The majority of the Delta cases in Wales have been focused around a cluster of cases in North Wales and a cluster of cases in South Wales, but now also starting to see unlinked cases in these areas and elsewhere in Wales.
The numbers of variant cases in Wales are reported on the Public Health Wales surveillance dashboard at 12pm on Monday and Thursday.
Public Health Wales is not currently reporting variants by health board, but can confirm that most health boards in Wales have reported cases.