A spokesman for the Kensington Palace confirmed on Wednesday that "Meghan's commitment was reduced slightly due to crowd management problems."
The Prince also participated in a ceremony at the National War Memorial, which commemorates both Fijian and British troops.
The duke and the duchess are on a tour of the region in several countries. After several days in Australia, the couple flew to Fiji on Tuesday, where they were warmly greeted by residents who lined the route from the airport, despite the rain. The couple will visit Tonga and New Zealand before returning to Australia.
The visit comes 65 years after the grandparents of Harry, Queen Elizabeth II and Prince Philip, visited the island nation after the coronation of the queen.
Harry and Meghan stayed at the same hotel as the Queen and Prince Philip in 1953, the Grand Pacific Hotel, and greeted supporters from the hotel balcony before attending a state banquet held in his honor by the country's president , Jioji Konrote.
On an official visit to the University of the South Pacific, both spoke, with Meghan giving a speech that promotes education and women's rights.
"Everyone should have the opportunity to receive the education they want, but more importantly, the education they are entitled to receive, and for women and girls in developing countries, this is vital," she said, dressed with a traditional lei from the South Pacific.
The Prince warned about the dangers of climate change, recognizing its effect on the low nations of the Pacific islands.
"We know that young people are the future of the Commonwealth (…) you will be the most affected by the global challenges we face, but you are the leaders who are creating the solutions," he said.
"One of the biggest challenges is, without doubt, climate change and everyone who lives here faces this threat in their daily lives."