Safari is the fastest browser for iPhones due to its integration with iOS. Apple has optimized Safari to work seamlessly with the iPhone's hardware, ensuring quick load times and efficient performance. That means you also get better battery life with Safari as compared to other third-party browsers. However, speed can depend on the websites you visit and how those sites are optimized for different browsers. Third-party browsers like Chrome may offer comparable pace in various conditions — but Safari's optimization for iOS typically gives it a speed advantage.