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How do Saturn’s inner moons differ from its distant outer moons?

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Saturn
Saturn Saturn and its spectacular rings, in a natural-color composite of 126 images taken by the Cassini spacecraft on October 6, 2004. The view is directed toward Saturn's southern hemisphere, which is tipped toward the Sun. Shadows cast by the rings are visible against the bluish northern hemisphere, while the planet's shadow is projected on the rings to the left.

Saturn’s moons are categorized into two distinct groups based on their orbital characteristics and origins:

Inner Moons

The inner moons are considered "regular" satellites. They orbit within approximately 3.6 million km of Saturn and follow prograde, low-inclination, and low-eccentricity orbits. It is believed that the eight largest of these moons formed in situ from a protoplanetary disk of material, similar to how planets formed around the Sun.1

Outer Moons

The outer group of moons orbits beyond 11 million km from the planet. These are "irregular" bodies characterized by large orbital eccentricities and inclinations. Notably, about two-thirds of these moons revolve in a retrograde fashion, moving opposite to the planet's rotation. Unlike the inner moons, these outer bodies are generally small—with the exception of Phoebe—and are believed to be captured objects or fragments rather than primordial moons.1