The pre-COP31 climate summit will transport the delegation more than 1000km from Fiji to visit the island nation on Tuesday, where its land sits an average of two metres above sea level.
But only one national leader from outside the Pacific is expected to attend the event, potentially limiting its reach.
The visit will take place on the second day of the pre-COP31 event, held a month before the United Nations' Conference of the Parties climate talks in Turkey, where Australia will host negotiations.
Leaders from nations including Mauritius, Tonga, Papua New Guinea, Vanuatu and the Cook Islands will attend the Tuvalu event, along with ministers from another 16 countries such as France, India, Singapore and New Zealand.
Representatives from the European Union and United Nations are also expected, and Climate Change Minister Chris Bowen said the turnout would be a first for the event, which was typically a "much more sedate" affair.
"This is the first pre-COP where ... world leaders have been invited at all," he said.
"As the president of Palau said, if you get one prime minister, you're doing well because prime ministers and presidents don't go to pre-COP."
Communities on Tuvalu's main island are expected to show off efforts to adapt and protect their coastlines from rising seas, erosion and storm surges, including a project that could reclaim 20 hectares of land by the end of 2026.
Pacific nations won the right to host the pre-COP event in a compromise after Australia lost its bid to host COP31 in Adelaide.
But Fiji Prime Minister Sitiveni Rabuka told the attendees that the event would be a vital to show the world the toughest impacts of climate change.
"We ask you to come to the Pacific because some things cannot be understood from a distance," he said.
"In the days ahead, you will stand on Tuvalu soils. There, the climate crisis is not a forecast, it is a king tide at the door ... and the hardest of questions: how long can we continue to stay?"
After landing in Nadi on Monday, Prime Minister Anthony Albanese said the summit would provide important context for nations outside the region.
"It is important that Pacific voices are heard because the Pacific is the front line of action on climate change," he said.
"For many of the nations represented by leaders here, it is literally a threat to their very existence, which is why the world must act."
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