RunDay: ランニング記録 ボイスガイド is a community-focused running application designed for iPhone users, offering a fully voice-guided experience. The app addresses common concerns for runners, including lack of information, motivation, and fitness management. It features a variety of running plans suitable for all levels, from beginners to advanced runners, including structured challenges and free running options.

In addition to its training capabilities, RunDay integrates with smartwatches like Apple Watch and Fitbit to track exercise history. The app also promotes community engagement through group features, allowing users to connect, compete, and support friends. Additional functionalities include a sound mixing system that adjusts music based on running intensity, shoe care tips, and the ability to share running achievements on social media.