There are no hard and fast rules for moving your child into an adult-sized single bed type. Some children move from a cot to a toddler bed, then to an adult bed, while others go straight from a cot to a single size bed frame. It really depends on the child. Many parents find that 2 years old is a good time to start thinking about the transition, but our toddler beds and mattresses will be a great fit for most kids until they’re around 3 or 4.