Mental-physical multimorbidity (the co-existence of mental and physical ill health) is highly prevalent and associated with significant impairments and high healthcare costs. While the sociology of chronic illness has developed a mature discourse on coping with long term physical illness the impact of mental and physical health have remained analytically separated, highlighting the need for a better understanding of the day-to-day complexities encountered by people living with mental-physical multimorbidity. We used the phenomenological paradigm of the lived body to elucidate how the experience of mental-physical multimorbidity shapes people's lifeworlds. Nineteen people with chronic obstructive pulmonary disease (COPD) and depression (defined as a score ≥8 on depression scale of Hospital Anxiety and Depression Scale) were recruited from secondary NHS care and interviewed at their homes. Data were analysed phenomenologically using van Manen's lifeworld existential framework of the lived body, lived time, lived space, lived relations. Additionally, we re-analysed data (using the same framework) collected from 13 people recruited from secondary NHS care with either COPD, rheumatoid arthritis, heart disease, or type 1 or type 2 diabetes and depression. The phenomenology of mental-physical multimorbidity was articulated through embodied and emotional encounters with day-to-day life in four ways: [a] participants' perception of lived time and lived space contracted; [b] time and [c] space were experienced as liminal categories, enforcing negative mood and temporal and spatial contraction; and [d] time and space could also be customised to reinstate agency and self-determination. Mental-physical multimorbidity negatively impacts on individuals' perceptions of lived time and lived space, leading to a loss of agency, heightened uncertainty, and poor well-being. Harnessing people's capacity to modify their experience of time and space may be a novel way to support people with mental-physical multimorbidity to live well with illness.