Smart wearable devices collect sensitive personal and health data, making them attractive targets for attackers. This case study compares the security mechanisms of two popular smartwatch models, the Amazfit GTS 4 and the Redmi Watch 5 Active, in terms of protecting users’ personal data. The article presents the results of a series of practical security tests analyzing access security, resistance to brute-force attacks, management of personal and health data, security of Bluetooth communication, update mechanisms, behavior in the event of loss or theft of the device, and notifications. The testing was carried out in real-world conditions using specialized hardware and software to analyze wireless communication. The results revealed significant differences in the level of protection implemented between the two models. The Amazfit GTS 4 was found to offer significantly more comprehensive personal data protection than the Redmi Watch 5 Active, which only meets basic requirements and relies on the user’s initiative in several areas. Finally, the article discusses recommendations for manufacturers and users in accordance with current IoT security standards.