You can usually claim Child Benefit once your baby’s birth has been registered, if you are responsible for their care and meet the UK eligibility rules. Only one person can claim for a child, so agree who will apply if you share care with someone else. Claims can generally be backdated by up to three months, but applying promptly may help protect National Insurance credits for the claimant. Check the latest rules and apply through the official GOV.UK Child Benefit service, especially if you or your partner may be affected by the High Income Child Benefit Charge.