Background Children with cancer were designated as clinically extremely vulnerable if they were to contract SARS‐CoV‐2 due to immune suppression in the early phase of the COVID‐19 pandemic. Our aim was to explore experiences, information and support needs, and decision making of parents with a child with cancer in response to this phase in the United Kingdom. Methods Parents of a child with cancer completed a survey at a time when the UK moved into a period of ‘lockdown’. An online survey was developed by the research team to capture parents’ experiences, information and support needs, and decision making, using closed statements and open text boxes. Descriptive quantitative analyses and qualitative thematic content analysis were undertaken. Findings One hundred seventy‐one parents/caregivers completed the survey. Eighty‐five percent were worried about the virus and they were vigilant about the virus (92%) or cancer symptoms (93.4%). For two‐thirds (69.6%), hospital was no longer considered a safe place. Eight overarching themes were identified related to the virus: (a) risk of infection; (b) information, guidance and advice; (c) health care provision; (d) fears and anxieties; or related to lockdown/isolation: (e) psychological and social impact; (f) keeping safe under lockdown; (g) provisions and dependence; and (h) employment and income. Conclusions This is the first study, to the best of our knowledge, to report experiences of parents of a child with cancer during the SARS‐CoV‐2/COVID‐19 pandemic. The majority of parents were worried about SARS‐CoV‐2 and transmitting the virus to their child. Hospital was no longer perceived to be a safe place, and parents were worried about suboptimal cancer care. Parents described fear and anxiety and the psychological, social and economic impact of isolation.