Royal Mail will trial the use of drones to deliver health and safety equipment, COVID-19 testing kits and other items to the Isles of Scilly.
It will be the first time an out-of-sight autonomous scheduled drone flight has been used between the UK mainland and an island, the company said.
Parcels will be flown to the airport in St Mary's by a drone which can carry up to 100kg of mail at a time, which is about the size of a typical delivery round.
The items will then be taken by a smaller drone to delivery points around the isles.
Amy Richards, a postwoman on the Isles of Scilly, said: "There are some really remote areas on these islands, and this is a terrific way to help us reach them.
"It's really important for us to do all we can to help all areas of the country stay connected, especially in these difficult times."
If the trial succeeds, Royal Mail said the technology could be used to support postal workers in delivering to remote areas in the UK.
Royal Mail chief commercial officer Nick Landon said: "This is part of our constant drive to incorporate the best and most innovative technologies into our network.
"We've seen a huge increase in parcel volumes since the start of the pandemic, and this is just one of the ways we are looking to support our postmen and postwomen in delivering fast and convenient services for all of our customers while reducing our carbon emissions."
The government-funded project is developed in partnership with DronePrep, Skyports, Consortiq Limited, the University of Southampton, Excalibur Healthcare Services and Windracers Limited.
Transport Minister Rachel Maclean said: "The UK is already a world leader when it comes to innovation in aviation and today's announcement is an exciting step forward for Royal Mail."