Background: During the COVID-19 pandemic, patients in the intensive care unit have been subjected to strict isolation precautions, and potentially long and complicated patient courses. The aim of the study is to provide an investigation of the experiences of isolation in COVID-19-positive patients in the ICU during the first phase of the COVID-19 pandemic in Denmark. Methods: The study was performed in a 20-bed ICU at a university hospital in Copenhagen, Denmark. The study is based on a phenomenological framework, Phenomenologically Grounded Qualitative Research. This approach provides insights into the tacit, pre-reflective and embodied dimensions of the specific experience under investigation. Methods included a combination of in-depth structured interviews with ICU patients 6–12 months after ICU discharge, and observations from inside the isolated patient rooms. The descriptions of experiences gathered through the interviews were subjected to systematic thematic analysis. Results: Twenty-nine patients were admitted to the ICU in the period 10 March and 19 May 2020. A total of six patients was included in the study. Themes consistently reported across all patients included (1) being objectified to degrees that implied self-alienation; (2) feeling a sense of being in captivity; (3) being in an experiential state of surrealism, and finally (4) experiencing extreme loneliness and intercorporeal deprivation. Conclusion: This study provided further insights into the liminal patient experiences of being isolated in the ICU due to COVID-19. Robust themes of experience were achieved through an in-depth phenomenological approach. Although, similarities in experiences compared to other patient groups exist, the precarious situation constituted by COVID-19 lead to significant intensifications across multiple parameters.