There is no definitive answer to this question, as it depends on the child's level of maturity and physical coordination. Some children as young as three or four years old may be able to use binoculars with adult supervision, while others may not be ready until they are six or seven. Ultimately, it is up to the parent or guardian to decide when their child is ready to use binoculars. If you are unsure, it is always best to err on the side of caution and start with a smaller, simpler toy such as a magnifying glass.