Quick answer: Most babies are ready to move from bassinet to cot at 3–6 months, or when they approach the bassinet’s weight/height limit. The transition is usually smooth with a consistent approach: maintain the same sleep environment variables and consider a gradual introduction through naps first.
When to make the transition
The practical triggers: approaching the weight limit of the bassinet (most list 4–9kg — check your model); the baby can push up on hands and knees (mobility creates a safety risk in a bassinet with lower sides); or the baby simply seems cramped and uncomfortable in the smaller space. Most families make the move between 3–5 months. Some bassinets accommodate babies to 6+ months — there’s no rush if the current arrangement is working safely.
Room-sharing: the safe sleep guideline
NHS, AAP, and Lullaby Trust guidance recommends room-sharing — baby in their own sleep space in your room — for at least 6 months, ideally 12 months. If the transition to a cot means moving to a separate room before 6 months, this goes against current safe sleep recommendations. Most families keep the cot in the parents’ room for 6 months and move to a separate room after that. When moving to a separate room, a monitor is useful if the house is large enough that sounds don’t travel.
Making the transition smooth
Replicate the sleep environment exactly: same white noise, same temperature, same bedtime routine. Babies associate sleep with specific environmental cues and maintaining these while changing only the sleep surface reduces disruption. Introduce the cot during naps first (lower stakes than overnight) — this familiarises the baby with the new surface before the overnight transition. Set the mattress at the highest position initially. Warm the mattress surface with a warm water bottle for 10 minutes before transfer, then remove it completely — a cold surface against warm arms is a significant transfer disrupter.
Cot safety reminders
Start with the mattress at the highest position. Lower to the mid position when the baby can sit independently (~6 months). Lower to the lowest position when the baby can stand (~9–10 months). Always buy a new mattress — never reuse a mattress from another baby. No soft items in the sleep space: no pillows, no bumpers, no toys until 12 months. Sleeping bag continues to be the recommended bedding — eliminates the loose blanket concern.
Frequently Asked Questions
My baby slept perfectly in the bassinet but won’t settle in the cot — what do I do?
Give it 5–7 consistent nights. The cot feels large and open after a snug bassinet. A continued swaddle (if the baby isn’t rolling), white noise, and the warm-mattress transfer technique together usually resolve the issue within a week. Some families place a rolled towel under the sheet along one edge to create a slight containment feeling — but never use a loose rolled towel that could move near the baby’s face.
Do I need to buy a new mattress for a second-hand cot?
Yes — always. The recommendation to avoid second-hand mattresses applies even between siblings. Buy new.
When can my baby have a pillow and blanket in the cot?
12 months is the guideline minimum. After 12 months, a light pillow and a blanket tucked firmly at armpit level are generally considered safe. Many families continue using sleeping bags beyond 12 months, which removes the blanket concern entirely.
Related Reading
Found this helpful? Sign up to the LylyMama newsletter — evidence-based answers to the questions every new parent actually has.
