Diabetes UK Cymru said 7.1 per cent of people aged 17 and over in Wales are living with the condition which is more than anywhere else in the UK.
This accounts for over 183,000 people, 6,000 up from this time last year.
The figures have been released to coincide with the launch of Diabetes Week, which was created to raise awareness of the condition.
It has been predicted that by Saturday, June 18, which marks the end of the week-long campaign, 4,500 people in the UK will have been diagnosed with diabetes.
As the number of people living with diabetes continues to grow, the charity is hoping to “highlight the many myths and misconceptions” which surround the “complex and often misunderstood condition.”
Diabetes UK Cymru’s director Dai Williams said they wanted to “set the record straight” and focus on the “realities of living with the condition.”
He added: “There is still a lack of understanding when it comes to people being aware of the seriousness of diabetes and this worries us at Diabetes UK.
“There are now the highest ever number of people living with diabetes in Wales, over 183,000. That’s 6,000 more people than were living with the condition during last year’s Diabetes Week, which really highlights the current scale of the crisis.”
In England, 6.37 per cent of people aged 17 and over have diabetes, and 5.6 per cent in Northern Ireland.
Scotland has the lowest amount at 4.8 per cent, although that figure is calculated slightly differently as it is a percentage of the whole population.