https://www.theverge.com/circuitbreaker/2018/10/19/17999220/apple-watch-usb-type-c-charging-cable

Continuing its move towards embracing USB Type-C, Apple has released a charging cable for the Apple Watch that uses the new connectivity standard, via Apple Insider. Using the new charger means you’ll be able to charge Apple’s wearable by plugging it into a modern MacBook, or any other laptop that’s made the switch to the more slimline port.

The new charger costs $29 / €35 / £29 with a cable that’s 0.3-m long. There’s no mention of a longer 1-m or 2-m variant being available like you can get with the USB Type-A charger. Charging time and power delivery are unlikely to be affected given that the induction charger appears unchanged.