Blazing sunshine and a red carpet lined with potted palms greeted Prince Harry as he arrived in Antigua on a Caribbean tour billed as formal but fun.
The prince will spend 15 days touring seven island nations as the Queen's representative.
The governor general of Antigua welcomed him with a reception at the newly restored Clarence House.
The prince re-opened the building - designed for King William IV when governor general in the 18th Century.
He also read out a message from the Queen in which she recalled her "fond memories" of visiting Antigua on three occasions between 1966 and 1985,
The prince also congratulated the Queen and the Duke of Edinburgh on their 69th wedding anniversary.
Earlier he made an unscheduled stop at Nelson's Dockyard, a Unesco World Heritage Site where Admiral Lord Nelson was based for four years in the 1780s.
Later, Harry is to join West Indian cricket legends Sir Vivian Richards, Sir Andy Roberts and Sir Curtly Ambrose at a sporting event near Antigua's capital St John's.
A Kensington Palace source said the tour would have a "formal feel" but there would be "plenty of fun".
Its build-up has been overshadowed after it emerged the prince was dating US actress Meghan Markle.
Earlier this month Prince Harry, 32, hit out at the media for subjecting Ms Markle to a "wave of abuse and harassment", issuing a rare but strongly worded statement.
Prince Harry's Caribbean tour
- The prince will visit six countries where the Queen is head of state
- Antigua and Barbuda, Barbados, Grenada, St Kitts and Nevis, St Lucia, and St Vincent and the Grenadines
- He will also tour the Commonwealth nation of Guyana
- The visit will mark the 50th anniversary of independence for Barbados and Guyana
- In Antigua and Barbuda Prince Harry will also mark the 35th year since independence
The palace source added that Prince Harry had been "looking forward to the tour for many months" and was "honoured" at being asked to represent the Queen.
"While this tour will necessarily have a more formal feel, he's pleased that he'll have plenty of opportunities to meet people from all walks of life. There should be plenty of fun along the way."