The couple will head to Manchester for the One Young World Summit, an event that brings together young leaders from more than 190 countries, on September 5.
Meghan, a counsellor for the organisation, will give the keynote address at the opening ceremony.
They will also meet a group of summit delegates doing “outstanding work on gender equality”, One Young World said.
The Sussexes will then head to Germany for the Invictus Games Dusseldorf 2023 One Year to Go event on September 6, before returning to the UK for the WellChild Awards in London on September 8 where Harry will deliver a speech.
Their visit to the UK will be the first time they have been back in the country since the Jubilee celebrations in early June, when they attended the service of thanksgiving at St Paul’s Cathedral.
It falls in the same week the new prime minister is due to be announced and asked to form a Government by the Queen.
Harry’s 96-year-old grandmother is expected to return to London from her annual summer break at Balmoral to carry out her head of state duties. It is likely the duke will want to visit her.
A spokesman 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.”
Security will be at the forefront of Harry’s mind as he travels from his home in California for the high profile appearances.
The duke, who quit as a senior working royal in 2020, is bringing legal action over a decision not to allow him to pay for police protection for himself and his family when in the UK.
Last month he won a bid to bring a High Court claim against the Home Office.
His challenge concerns the February 2020 decision of the Executive Committee for the Protection of Royalty and Public Figures (Ravec) over his security, after being told he would no longer be given the “same degree” of personal protective security when visiting.
The royal family has been bracing itself for Harry’s coming tell-all book, which he has vowed will be an “accurate and wholly truthful” account of his life.
The memoirs were expected to be published late this year by Penguin Random House, but a release date has yet to be confirmed.
There will be concern in royal quarters the duke will delve into his rift with his brother, the Duke of Cambridge, his troubled relationship with his father, the Prince of Wales, his view of stepmother the Duchess of Cornwall and the turbulent fallout of Megxit.
Harry and Meghan accused the royal family of racism in their controversial Oprah Winfrey interview last year, saying an unnamed royal made a racist remark about their son Archie before he was born, and the institution failed to help a suicidal Meghan.
It is thought unlikely the couple will bring their children Archie and Lili on the working trip.