Aims and Objectives We aimed to determine the impact of COVID‐19 related home confinement on the paediatric population by focusing on anxiety, behavioural disturbances and somatic symptoms. Background To limit the spread of the COVID‐19 outbreak, governments have imposed nationwide lockdowns to prevent direct contact; this has affected everyday lives and activities such as attending school classes. Such isolation may have impacted children’s anxiety levels. Design and Methods We conducted a cross‐sectional observational study using a web‐based anonymous questionnaire from 22–26 April, 2020, among children ( N = 2,292) in Spain. For children below 7 years of age, parents reported the children’s behavioural, emotional and somatic symptoms and family environment data on a questionnaire designed by the researchers. Children over 7 years answered the Revised Children’s Manifest Anxiety Scale either independently or with their parents’ assistance. Results Children over 7 years, boys in particular, scored high on the anxiety spectrum. Moreover, participants who knew someone who had suffered from COVID‐19 at home or whose parent was directly involved in the pandemic, obtained higher Total Anxiety scores. Significantly high values were found in all aspects of anxiety among those who feared infection or whose parents been unemployed. Of the children below 7 years, 56.3% had four or more anxiety‐related symptoms, the most frequent of which were tantrums, emotional changes, restlessness and fear of being alone. The number of symptoms reported was significant when someone in the family home had been infected with COVID‐19. Conclusions The COVID‐19 home confinement had a significant impact on children, causing anxiety, behavioural problems and somatic manifestations. Relevance to clinical practice Nurses play a key role in screening children who have experience confinement owing to the COVID‐19 pandemic in order to detect early anxiety symptoms using tele‐health. Suitable direct interventions can then be implemented or interdisciplinary manage could be started.