Ui-te-Rangiora or Hui Te Rangiora is a legendary Polynesian navigator from Rarotonga who is claimed to have sailed to the Southern Ocean and sometimes to have discovered Antarctica.
According to a 19th-century interpretation of Rarotongan legend by Stephenson Percy Smith, Ui-te-Rangiora sailed south and encountered an area he called Tai-uka-a-pia (interpreted by Smith as a frozen sea), "a foggy, misty, and dark place not seen by the sun" where rocks grow out of the sea. Smith interpreted this as referring to the ice floes and icebergs in the Southern Ocean, due to the ice floes being similar to arrowroot powder (referring to Tacca leontopetaloides, Polynesian arrowroot). This has led others to conclude that Ui-te-Rangiora was the first person to discover Antarctica.
The interpretation of Ui-te-Rangiora reaching Antarctic waters has been questioned. Anderson et al. note that there is no mention of an Antarctic voyage in the original legend, and that it is first mentioned in the story of his descendant Te Aru Tanga Nuku, who wished to "behold all the wonderful things on the ocean" seen by his ancestor. Te Rangi Hīroa considers the legend so contaminated by European material that it cannot be accepted as accurate and ancient. As the Cook Islands Māori language had no pre-European word for ice or frozen, interpreting Tai-uka-a-pia as a frozen sea is simply a mistranslation, and instead it should be translated as "sea covered with foam like arrowroot". New Zealand iwi Ngāi Tahu considers the legend to be a mythic origin story rather than a historical voyaging narrative.
It has been suggested that the folklore of the islanders reflected an actual event, namely a sea area covered with a dense layer of floating pieces of pumice resulting from some undersea volcanic eruption. Such a 25 000 km2 sea surface was sighted in 2012 in the area of Kermadec Islands, with a 60 cm thick bright white layer resembling a shelf glacier.