It was discovered in February 2020 after the Pine Island Glacier melted away from around it, and is named after Sif, an Æsir goddess associated with the Earth in Norse mythology.

It is plausible that the island emerged as a result of post-glacial rebound, a process in which retreating glaciers relieve pressure on the ground, causing it to rise.

[2] On February 11, 2020, marine geologist and crew member Julia Wellner announced the island's discovery via Twitter, stating that a crew member aboard the ship had spotted the rocky outcropping of granite, visible beneath a 'mushroom' of remnant ice.

Despite the island being visible by satellite, its icy cap prevented it from being discovered earlier, as it blended in with the surrounding glacier.

[2] On February 23, photos of the researchers' first landing on the island were posted by Wellner on her Twitter account.