The watch starts at $399 (£399, AU$649) for the GPS-only model, and $499 (£499, AU$799) for both GPS and cellular.
You can order the Apple Watch Series 5 now and it will be available in stores on Sept. 20.
The Watch Series 5 will have an always-on display while delivering, Apple says, the same all-day, 18-hour battery life as previous models.
Always-on is something other watches have had, and we're excited to see it come on the Apple Watch.
Much like other smartwatches, especially last year's Qualcomm Snapdragon 3100 Wear OS watches, the color watch faces go into a dimmer, yet still slightly animated mode when you turn your wrist away.
The watch faces change colors a bit and brighten up when you turn your wrist back.
The always-on mode works only when it's on a wrist, and with Apple's watch faces and the Workout app.
Other features include a native compass. During our brief time with it, we could get directional bearings quickly, and it seemed to perform fine in a crowded Steve Jobs Theater demo room. Compass complications show up in a few watch faces, too.
Click through for more images of the new Apple Watch.
The Apple Watch Series 5 doesn't feel dramatically different, but having an always-on display is a big and overdue change that we didn't expect, but are glad to welcome
In addition to the debut of the Watch Series 5, Apple announced it has permanently lowered the price of its Apple Watch 3, which launched in 2017, to $199 (£199, AU$319).
For more info, read CNET's Apple Watch Series 5 review.