There is a global mental health crisis with youth aged 15 to 24 experiencing high levels of mental distress. Thus, adolescence is a critical developmental period in which to provide high-quality mental health interventions. With greater access to technology, Crisis Text Lines (CTLs) are frequently used by adolescents who are seeking support for their mental health. However, very few studies have examined youth’s perspectives on using these services. This phenomenological qualitative study will use semi-structured interviews to collect first-person perspectives from 16 to 18-year-olds about their experiences using a New Zealand-based mental health CTL within the previous 12 months. Data was analysed using inductive reflexive thematic analysis. Findings consisted of four main themes; the reasons why youth contact CTL services, youth experiences of helpful and unhelpful conversations, the significance of the therapeutic relationship, and youth suggestions for improvements of CTL services. The findings of this study will enhance our understanding of youth experiences of using a CTL. It may also have important implications for the development, delivery, and improvement of clinical services. Awareness and understanding of youth experience may also help to ensure CTL continues to benefit youth who use these services.