HIV represents a "biographical disruption", interrupting the continuity of life and fostering a sense of vulnerability. The transition of HIV into a chronic condition, coupled with extended life expectancy, necessitates significant lifestyle adjustments, making adaptation and navigation through uncertainties essential. Interpretative phenomenological analysis was used to investigate the lived experiences and adaptation processes of gay men in Greece who are living with HIV. Semi-structured interviews were conducted with seven HIV-positive gay men, recruited from two Greek NGOs that support individuals living with HIV. Investigator triangulation was used to interpret textual material, heightening credibility and reducing bias, thereby enhancing the findings' reliability. The analysis identified a superordinate theme, "Being Vulnerable Enough: Negotiating Uncertainties and Adapting in the HIV Experience", which encompasses three themes: "The Moment of Division: Fear, Uncertainty, and Vulnerability after an HIV Diagnosis", "Grief and Negotiation: Navigating Daily Life Through the Lens of Loss", and "Reclaiming Self: Shaping 'My HIV Identity' to Fit on My Terms". The initial shock of HIV diagnosis introduces a sense of vulnerability, with participants confronting fear, despair, and grief over the loss of health and the disruption of their anticipated life flow. Being vulnerable enough enables individuals to adapt to life with HIV by managing uncertainties through creating certainties with small daily decisions, in a non-linear, ongoing process of negotiation and reassessment, without the need to eliminate all uncertainties.