This study examined the effects of spontaneous roleplay activities on the English-speaking skills of Grade 12 students at St. Vincent’s College Incorporated – Basic Education Campus during the school year 2025–2026. Anchored on Vygotsky’s Sociocultural Theory and the concept of Communicative Competence, the research explored how interaction, scaffolding, and authentic communication contribute to learners’ fluency, pronunciation, vocabulary, and confidence. A quasi-experimental crossover design was utilized involving two intact classes that alternately experienced roleplay and non-roleplay conditions over two days. Data were gathered through a standardized rubric and analyzed using weighted mean, standard deviation, independent sample t-test, and paired sample t-test. Results on Day 1 showed that the control group and experimental group achieved mean scores of 90.8 and 91.3 in fluency, 90.2 and 91.7 in pronunciation, 90.5 and 91.4 in vocabulary, and 90.8 and 92.1 in confidence, respectively. After the crossover on Day 2, both groups recorded similar outcomes across all components, with only minor variations. Findings indicate that spontaneous roleplay activities benefited lower-performing students by improving measurable speaking skills, while advanced learners demonstrated stable performance due to a ceiling effect. Overall, the study concludes that roleplay is an effective strategy for enhancing speaking proficiency and strengthening communicative confidence in senior high school students.