[12] Siarnaq was discovered on 23 September 2000, by an international team of astronomers consisting of Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew Holman, Brian G. Marsden, Phil Nicholson and Joseph A.

[2] The discovery of Siarnaq formed part of an observational campaign to search for distant irregular satellites around Saturn.

The campaign was coordinated by Gladman in late 2000 using various ground-based telescopes equipped with sensitive CCD cameras to survey Saturn's Hill sphere, the region within which satellites can have stable orbits around the planet.

[14][15] In September 2000, Gladman and collaborators conducted a wide-area survey around Saturn down to a R-band limiting magnitude of 24.5 with the 3.6-meter Canada-France-Hawaii Telescope (CFHT) at the Mauna Kea Observatory in Hawaii.

Siarnaq is said to reside at the bottom of the ocean and to have conceived all sea life, which she will withhold from Inuit hunters when angered.

In some versions of Inuit legend, Siarnaq was once a beautiful maiden who was tricked into marrying a bird-man and then was rescued by her father.

[14][24] Kavelaars was advised by his colleagues to deviate from the traditional Greco-Roman mythology theme for Saturnian moons and instead propose names from different cultures.

Throughout late 2000, Kavelaars spent several months consulting Amerindian scholars for appropriate name suggestions that were both multicultural and Canadian in origin.

[6] Siarnaq is light red in color, and the Siarnaupian (Siarnaqan)[c] spectrum in the infrared is very similar to the Inuit-group satellites Paaliaq and Kiviuq, supporting the thesis of a possible common origin in the break-up of a larger body.

[7] Siarnaq displays a light curve with three maxima and minima over a full rotation, implying a roughly triangular shape similar to that of Ymir.

[e] This corresponds to a sideways axial tilt, indicating that Siarnaq experiences long, extreme seasons similar to the planet Uranus.