Which planet has the most moons discovered so far?

Saturn, which passed Jupiter in 2023 and is now credited with over 270 - a number that keeps moving, because at the small end it becomes a matter of definition and of how good the telescope is. Many of the recent additions are irregular objects a few kilometres across on distant tilted orbits, almost certainly captured rather than formed there.

The interesting moons are the large ones. Titan is bigger than Mercury and has a thick nitrogen atmosphere with lakes and rivers of liquid methane, rain, and dunes - the only other place in the Solar System with standing liquid on its surface. Enceladus, tiny by comparison, vents water from a subsurface ocean through cracks at its south pole.

The count is not really a competition. Jupiter and Saturn both sit in a region rich in leftover material with enough gravity to capture almost anything that drifts past, and the race between them will keep swapping as survey telescopes improve. What the numbers really record is the state of our instruments rather than the state of the Solar System.