Activity tracker watches can vary in terms of their water resistance levels. Some activity tracker watches are designed to be waterproof and can be submerged in water for swimming or other water-based activities. These watches often have a specific water resistance rating, such as 5 ATM or 50 meters, indicating their ability to withstand water pressure at various depths. However, it is important to note that not all activity tracker watches are waterproof. Some may only be water-resistant or splash-proof, which means they can handle minor exposure to water but should not be submerged. It is always recommended to check the specifications and water resistance rating of an activity tracker watch before using it in water-related activities.