When you buy through our links, Business Insider may earn an affiliate commission. Learn more

A side by side photo of someone wearing an Apple Watch Series 9 and an Apple Watch Ultra 2
The Apple Watch Series 9 (left) and the Apple Watch Ultra 2 (right)

The Apple Watch Series 9 and Ultra 2 are Apple's flagship smartwatches. While they share many similarities — the ability to track workouts, monitor sleep habits, and send call, text, and app notifications — some differences make one more suitable to some people than the other. 

For instance, those wanting a premium smartwatch experience in a sleek form factor should opt for the Series 9. Conversely, if multi-day battery life, advanced activity tracking, and a rugged, durable design are preferred, then the Ultra 2 is the better choice.