Barclays Bank on the Isles of Scilly is to close at midday today.
Account holders were informed by letter of the decision to shut the St Mary's branch in May.
Staff hosted an open day last week, inviting customers to enjoy drinks and nibbles to say goodbye.
Barclays told This is Scilly: "This is not a decision we have taken lightly and we recognise that this is disappointing news for some of our customers on the Isles of Scilly.
"We’re committed to the UK Access to Banking Standard. All our customers will have received a letter informing them of the closure and we have extended the 12 weeks’ notice period to allow additional time to support our customers in the transition. A ‘decision to close document’ and posters have been on display and available in the branch and we have been supporting customers in identifying alternative ways to undertake their banking once the branch closes.
"We have been working closely with our branch colleagues to discuss the various options available including relocating to the mainland, redundancy and finding alternative local employment. At the branch we have hosted nibbles and drinks to say goodbye to our customers."
Michael Watts, Barclays Community Banking Director for Cornwall and Devon, said: “The way people do their banking is changing as they increasingly use online, telephone and mobile devices, with over 70% of customers in the Isles of Scilly also using these channels.
“This trend has impacted customer usage of the branch with a decline of 27% over the last two years alone, which is why we have taken the difficult decision to close the branch on Thursday 18th October.
“We hope that the availability of the local Post Offices along with our range of digital and telephony channels will help to ease the transition for our customers.”
How the St Mary's branch was used in the last two years: