watchOS 10 is the tenth release of watchOS, shipped September 18, 2023 — the platform's biggest visual rethink since launch. Apps went full-screen and glanceable, widgets returned via the Smart Stack (turn the Crown from any face to scroll a relevance-sorted pile), and the hardware buttons remapped: side button to Control Center, Crown to the Stack — a navigation reshuffle that drew a re-learning grumble and then settled.

Cycling workouts paired with iPhone as a live full-screen bike computer with power-meter support and FTP zones; hiking gained topographic maps, waypoints, and cell-coverage tracking; and mental-state logging joined daylight-time tracking in the health ledger.

The Smart Stack; full-screen app redesigns; remapped buttons; cycling power and Bluetooth sensor support; topo maps and waypoints; state-of-mind logging; the Snoopy, Palette, and Solar Analog faces; NameDrop from the wrist; and offline Maps mirroring.

The Smart Stack became the platform's second surface — the widget layer every subsequent release feeds (live activities, suggestions) — and the full-screen design language carried into the Liquid Glass era. The Snoopy face, by informal consensus, became the most-worn software Apple shipped that year.