Meghan and Harry's last appearance came as the Queen celebrated 70 years on the throne.
The Sussexes will also visit Germany as part of their trip to support “several charities close to their hearts”.
The couple will travel to Manchester for the One Young World Summit, an event which brings together young leaders from more than 190 countries, on September 5.
The Duchess of Sussex is a counsellor for the organisation, alongside Justin Trudeau, Sir Richard Branson, and Jamie Oliver.
They will then head to Germany for the Invictus Games Dusseldorf 2023 One Year to Go event, before returning to the UK for the WellChild Awards on September 8.
Their visit to the UK will be the first time they have been back in the country since the Platinum Jubilee celebrations in early June.
A spokesperson for the couple said: “Prince Harry and Meghan, the Duke and Duchess of Sussex, are delighted to visit with several charities close to their hearts in early September.”
It is not known whether Meghan and Harry will be joined by their two children – Archie and Lilibet.
The Sussexes kept a low profile during their last visit and were booed outside St Paul's Cathedral.
But the couple took the time to see the Queen, in what was the first time Her Majesty met her granddaughter Lilibet in the UK.
They did not stand alongside the Royal Family's inner circle during the Trooping the Colour ceremony.
Instead, they watched the parade from the Major General's Office.
Meghan Markle and Prince Harry
PA Features Archive/Press Association Images
Meghan Markle and Prince Harry on their last UK visit
DYLAN MARTINEZ