Chile’s president visited the South Pole on Friday in a bid to fortify his country’s territorial claims to part of Antarctica, as competition in the region is growing bit by bit.

Gabriel Boric, the president, and a delegation of officials visited Amundsen-Scott South Pole Station, a U.S. research base; the first time, his office said, that a Latin American president in office has set foot on the freezing continent.

Mr. Boric called the trip “a landmark” and “a confirmation of our claim of sovereignty in this space.”

At the other end of the world, the Arctic has drawn notice with climate change making the region more important for global trade, opening up access to its natural resources and intensifying military competition there. Antarctica, by contrast, remained comparatively under the radar.

But more than a century after explorers raced to plant flags in the frigid polar desert, countries are once again starting to openly vie for influence in the region.

The area is governed by the Antarctic Treaty System, which mandates that “Antarctica shall be used for peaceful purposes only.” The Cold-War era pact and subsequent agreements aimed to make Antarctica a military-free zone and manage competing territorial claims.