Artificial Intelligence (AI) has become a cornerstone of modern smartphone functionality, significantly enhancing user experience, security, and efficiency. This paper presents a functional comparison and performance analysis of AI usage in iOS and Android, focusing on key areas such as voice assistants (Siri(Speech Interpretation and Recognition Interfac) vs. Google Assistant), AI-driven security features (Face ID vs. Face Unlock), machine learning frameworks (Core ML vs. TensorFlow Lite), computational photography, battery optimization, and augmented reality (ARKit vs. ARCore). The study highlights how AI-powered advancements improve system responsiveness, personalization, and automation while addressing challenges related to privacy, data security, and computational efficiency. Our analysis demonstrates that Apple’s AI approach prioritizes on-device processing and privacy, whereas Google leverages cloud-based AI for broader functionality. As AI continues to evolve, future developments in edge AI, federated learning, and neural processing units (NPUs) will further shape the landscape of mobile intelligence. This comparative study provides insights into the strengths and limitations of AI in both ecosystems, offering a roadmap for future AI-driven innovations in smartphone technology.