The competition watchdog found that a basket of groceries in Jersey is a third more expensive than at the cheapest UK supermarkets.
The Jersey Competition Regulatory Authority (JCRA) also found a 12% difference between Jersey and the UK in the price of the same basket of shopping at the same retailer.
The JCRA has published its final report following its study of the local groceries market. Its initial findings were released in June.
It says the average islander sets aside 9% of their weekly household budget to fund their food shop.
It comes as prices in supermarkets have risen 15% in the year to June 2023, although Jersey's inflation rate reflects trends seen in other jurisdictions.
The report concludes there are 'no significant competition issues with the local market'.
Peter Hetherington, Chief Economist at the Authority, says comprehensive survey data indicates that Jersey customers are 'well-served'.
"Higher on-island operating costs and the lack of low-price suppliers, however, do mean that Jersey consumers are paying more for their groceries."

Credit: Infographic from JCRA Groceries Market Study Final Report: Findings and Recommendations.
The JCRA found that the higher prices here are primarily due to freight, labour costs and tax differences.
The watchdog says Jersey's retailers are 'not making excessive profits', and revenue is inline with expectations and benchmarks.
Its study has also found that people tend to shop around to find the best deals, and the competition in the market works well.
The Authority has made three recommendations, which include:
- Encouraging more competition by improving price transparency through the Jersey Consumer Council's price comparison service.
- Maintain a competitive and dynamic market by minimising entry barriers, such as planning and promoting Jersey as a testbed for new ideas.
- And to follow up on recommendations on Freight Logistics to increase competition and reduce freight costs.

Island Healthcare Fund created
Maison des Amis gets official opening
Black Butter making is back, and your help is needed!
Haut Du Mont trial: Workers 'clearly' not following Island Energy procedures, court hears
More rain in one October day than the whole of September
Government gives £150k to get Jersey athletes to 2027 Island Games
Mansell Collection scales back after fall in motorbike sales
Jersey Zoo announces death of Biggy the tortoise