List of Saturn's moons
This list of Saturn's moons covers the major and notable moons: the seven large round moons, the small moons tied to the rings, the Trojan companions, and the largest irregular satellites. Saturn has 274 confirmed moons in total, but most are irregular moons a few kilometers across with poorly known sizes, so they are summarized rather than tabulated. Values are rounded; distances are average orbital radii measured from the center of Saturn.
Contents
The main moons at a glance
The seven large moons account for almost all of the mass in Saturn's system. Titan alone carries about 96% of it; Rhea, Iapetus, Dione and Tethys share most of the remainder.
| Moon | Mean diameter | Distance from Saturn | Orbital period | Discovered |
|---|---|---|---|---|
| Mimas | 396 km | 185,500 km | 0.94 days | 1789, William Herschel |
| Enceladus | 504 km | 238,000 km | 1.37 days | 1789, William Herschel |
| Tethys | 1,062 km | 294,600 km | 1.89 days | 1684, G. D. Cassini |
| Dione | 1,123 km | 377,400 km | 2.74 days | 1684, G. D. Cassini |
| Rhea | 1,527 km | 527,100 km | 4.52 days | 1672, G. D. Cassini |
| Titan | 5,150 km | 1,221,900 km | 15.95 days | 1655, Christiaan Huygens |
| Iapetus | 1,469 km | 3,560,800 km | 79.3 days | 1671, G. D. Cassini |
Full table of notable moons
Ordered by distance from Saturn. Diameters of small, irregularly shaped moons are mean values and approximate.
| Moon | Mean diameter | Distance from Saturn | Orbital period | Discovered |
|---|---|---|---|---|
| Pan | about 28 km | 133,600 km | 0.58 days | 1990, Mark Showalter (Voyager 2 images) |
| Daphnis | about 8 km | 136,500 km | 0.59 days | 2005, Cassini imaging team |
| Atlas | about 30 km | 137,700 km | 0.60 days | 1980, Voyager 1 |
| Prometheus | about 86 km | 139,400 km | 0.61 days | 1980, Voyager 1 |
| Pandora | about 81 km | 141,700 km | 0.63 days | 1980, Voyager 1 |
| Epimetheus | about 116 km | 151,400 km | 0.69 days | 1966, Richard Walker |
| Janus | about 179 km | 151,500 km | 0.69 days | 1966, Audouin Dollfus |
| Mimas | 396 km | 185,500 km | 0.94 days | 1789, William Herschel |
| Methone | about 3 km | 194,000 km | 1.0 days | 2004, Cassini |
| Pallene | about 5 km | 212,000 km | 1.15 days | 2004, Cassini |
| Enceladus | 504 km | 238,000 km | 1.37 days | 1789, William Herschel |
| Tethys | 1,062 km | 294,600 km | 1.89 days | 1684, G. D. Cassini |
| Telesto | about 25 km | 294,600 km | 1.89 days | 1980, ground-based observers |
| Calypso | about 21 km | 294,600 km | 1.89 days | 1980, ground-based observers |
| Dione | 1,123 km | 377,400 km | 2.74 days | 1684, G. D. Cassini |
| Helene | about 35 km | 377,400 km | 2.74 days | 1980, Pierre Laques and Jean Lecacheux |
| Polydeuces | about 3 km | 377,400 km | 2.74 days | 2004, Cassini |
| Rhea | 1,527 km | 527,100 km | 4.52 days | 1672, G. D. Cassini |
| Titan | 5,150 km | 1,221,900 km | 15.95 days | 1655, Christiaan Huygens |
| Hyperion | about 270 km | 1,481,000 km | 21.3 days | 1848, W. C. and G. P. Bond; William Lassell |
| Iapetus | 1,469 km | 3,560,800 km | 79.3 days | 1671, G. D. Cassini |
| Phoebe | about 213 km | 12,944,000 km | about 550 days (retrograde) | 1899, William H. Pickering |
Janus and Epimetheus share practically the same orbit and trade places every four years (Janus and Epimetheus). Telesto and Calypso sit at the Lagrange points of Tethys, Helene and Polydeuces at those of Dione (Trojan moons). Methone, Pallene and the even smaller Anthe (about 1 km, found in 2007) orbit between Mimas and Enceladus and are known as the Alkyonides. Aegaeon, well under 1 km across and discovered in Cassini images in 2008, orbits within an arc of the G ring.
How to read the table
Diameter. Only the seven largest moons are massive enough for their own gravity to pull them into a nearly round shape. Hyperion, at about 270 km, is the largest known moon that is distinctly irregular. For elongated bodies like Pan or Prometheus, a mean diameter hides a shape that can differ by a factor of two between axes.
Distance and period. Orbital period rises with distance, as Kepler's third law requires: Pan circles Saturn in under 14 hours, Phoebe takes about a year and a half. The inner moons from Pan to Pandora orbit within or just outside the main rings, which end at the F ring about 140,000 km from the planet's center.
Discovery. The table mirrors the history of astronomy: telescopic discoveries from the 17th to 19th centuries, Phoebe as the first photographic discovery (1899), ring-plane crossings in 1966 and 1980, the Voyager flybys, and finally the Cassini orbiter. The detailed chronology is in how many moons Saturn has.
The irregular moons
More than 240 of Saturn's moons are irregular satellites orbiting millions of kilometers out on inclined, eccentric paths, most of them retrograde. After Phoebe, the largest are a few tens of kilometers across, such as Siarnaq (Inuit group), Albiorix (Gallic group) and Ymir (Norse group), all among the 12 irregular moons found by a ground-based survey in 2000. Their sizes are estimated from brightness with an assumed reflectivity, so they carry wide margins of error. The groups, their likely origin and naming rules are explained on the irregular moons page.
FAQ
What are the names of Saturn's main moons?
In order of distance, the seven major moons are Mimas, Enceladus, Tethys, Dione, Rhea, Titan and Iapetus. Hyperion and Phoebe are the best-known of the smaller moons.
What is the closest moon to Saturn?
Among named moons, Pan, orbiting inside the Encke Gap about 133,600 km from Saturn's center, is the innermost moon with a well-determined size. Among the large round moons, Mimas is closest.
Which of Saturn's moons is the farthest?
Of the notable moons, Phoebe orbits farthest, about 12.9 million km from Saturn. Some small irregular moons orbit even farther, more than 20 million km out.
Are all of Saturn's moons named?
No. Many of the 274 confirmed moons, especially those found since 2019, still have only provisional designations such as S/2004 S 24. The IAU assigns names from Norse, Gallic and Inuit mythology over time.