Crowds of people stood in the rain to witness the royal couple wave from the GPH balcony.
The royals have been touring Australia for the Invictus Games, a multi-sport event founded by Harry for wounded ex-service personnel, which is now under way in Sydney.
Her baby isn't even here yet, but the mom-to-be has already been keeping her little one safe while on her first royal tour with Prince Harry, 34.
Earlier, Prince Harry told those gathered for a state dinner in Suva the ties between Fiji and the United Kingdom ran deep and the two countries shared Commonwealth values, a love of rugby and a sense of humour.
Kensington Palace announced that Meghan was expecting on the eve of the couple's first tour outside the United Kingdom and Ireland.
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A day after Kensington Palace announced Meghan's pregnancy, Harry told fans in Australia, "We also genuinely couldn't think of a better place to announce the upcoming baby...whether it's a boy or a girl".
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At 11am this morning the Duke will travel to Colo i Suva Forest Park and the Duchess to the British High Commissioner's Residence before taking a tour of the Suva Market at 11.30am.
They will remain in Fiji carrying out engagements until Thursday, when they'll fly Tonga for more engagements, before returning to Sydney to close Harry's Invictus Games. The couple will then finish their tour with a four-day visit to New Zealand.
Meghan followed medical advice to cover up and minimise the risk of Zika infection, donning a long-sleeved white dress with a matching hat.