Teaching other students in a face-to-face manner has been shown to effectively foster both one's own and their learning. This study experimentally investigated whether and how tutors and tutees academically benefit from three phases of face-to-face teaching: preparing-to-teach, initial-explanation, and interaction phases. Japanese undergraduates (n = 80) acted as tutors or tutees in peer tutoring. After studying with the expectation of teaching face-to-face or taking a test (the preparing-to-teach phase), tutor participants provided tutee participants with initial instructional explanations, without asking or answering questions (the initial-explanation phase), and then engaged in a question-and-answer period (the interaction phase). Tutor and tutee participants learned better by providing and receiving higher-quality explanations in the initial-explanation and interaction phases. Face-to-face teaching vs. test expectancy had no effects on the quality of tutor participants' explanations or their learning outcomes. The results suggest that both the initial-explanation and interaction phases contribute to learning by teaching face-to-face, whereas the preparing-to-teach phase does not.