Automatic watches do not require batteries as they are powered through the kinetic energy the wearer generates with the movement of their arm.

Does an automatic watch use batteries?

An automatic or self-winding movement is also a mechanical caliber, but it doesn't require manual winding. ... As long as it is worn, an automatic watch will keep running without the need for manual winding or battery. Automatic movements are prevalent in luxury watches today.

How long do automatic watches last?

For an average automatic watch, you're looking at between 40-50 hours of life. There are some that last longer, but this is typical. And for most people, that's plenty of time. If this is a watch that you are going to wear every day, you only need about 30 hours of wound up energy.