S/2025 U1 is a satellite of Uranus with an estimated diameter of 8-10 km, making it the smallest moon of the planet.
The discovery was announced on 19 August 2025 by a team of astronomers led by Maryame El Moutamid, found on JWST images from 2 February 2025. It orbits 56 250 km away from the planet, between Ophelia and Bianca, and has an orbital period of 9.6 hours.
Like the other inner moons of Uranus, it follows a nearly circular orbit along Uranus's equatorial plane. Due to its small size, it appears extremely faint with a near-infrared (H-band) apparent magnitude of 25.5—too faint to have been seen by the Hubble Space Telescope and Voyager 2.
S/2025 U 1 is the provisional designation of this unnamed moon. By convention, the moons of Uranus are named after characters from the plays of William Shakespeare and Alexander Pope. A proper name will be given once it is approved by the International Astronomical Union, discussions for a name are already ongoing.