It was discovered by Matthew J. Holman, John J. Kavelaars, Tommy Grav, Wesley C. Fraser and Dan Milisavljevic on August 14, 2002.

[7] Halimede, like many of the outer satellites of Neptune, is named after one of the Nereids, the fifty daughters of Nereus and Doris.

Before the announcement of its name on February 3, 2007 (IAUC 8802), Halimede was known by the provisional designation S/2002 N 1.

The yellow segments extend from the pericentre to the apocentre, showing the eccentricity.

[9] Halimede is about 62 kilometers in diameter (assuming an albedo of 0.04)[5] and appears neutral (grey) in the visible light.