When to Move Your Baby From a Moses Basket to a Cot

Act on the first of these you see, whichever it is:

• Rolling, or trying to. A moses basket has shallow sides. A baby who can roll can tip weight against them, and that is the clearest stop sign there is.
• Pushing up on hands or sitting unaided. Same problem from a different angle: the sides are no longer a meaningful barrier.
• The weight limit. Every basket has one, usually printed on the label or in the manual. Check yours rather than guessing; baskets vary.
• They fill the basket. Head near one end, feet touching the other, or waking themselves by knocking the sides. Cramped sleep is poor sleep, and it only goes one way.
• The basket is working harder than you are. Visible bowing, a sagging mattress or a wobbly stand all end the basket's service life regardless of your baby's age.

None of this requires waiting for a milestone birthday. Equally, a long, sturdy baby who is happy and still under the weight limit at five months is fine where they are, as long as they are not rolling.

The NHS says your baby should sleep in the same room as you for every sleep for at least the first six months. Since most babies leave the basket around three to four months, that creates a gap, and there are three honest ways to bridge it:

• Cot in your bedroom. The simplest answer if your room fits one. The cot moves to the nursery at six months, or stays put as long as you like.
• Bedside crib until six months, then the cot. The popular route. A bedside crib is bigger than a basket, so it buys the months the basket cannot, and it sits flush against your bed. The catch is crib mattress sizes, which vary model by model; a Tutti Bambini CoZee takes 83 x 52 cm while a Joie Kubbie Sleep takes 87 x 52 cm, so check your exact model.
• Straight to the cot in the nursery, before six months. This is the one to avoid. Room-sharing to six months is not a soft recommendation; it is core NHS and Lullaby Trust safer sleep guidance, because it reduces the risk of sudden infant death syndrome. If the cot will not fit in your room, a compact crib that will is the better move until six months.

Choosing between a cot and a cot bed for the destination? That decision has its own trade-offs; our cot vs cot bed guide covers them properly.

The safer sleep rules do not change when the bed gets bigger. For the cot itself:

• A mattress that fits, firm and flat. The Lullaby Trust's wording is "firm, flat and protected by a waterproof cover", with no gaps between mattress and frame. Fit is where cots catch people out, because sizes are not standardised: most cots take 120 x 60 cm and most cot beds 140 x 70 cm, but brands such as Boori and SnuzKot use their own sizes. Look your cot up rather than buying by category, and see our sizes guide for the full picture.
• An empty cot. The NHS list is blunt: no pillows, duvets, cot bumpers, loose blankets, soft toys, pods or nests. A firm mattress, a fitted sheet and your baby in a correctly sized sleeping bag is the complete kit.
• Feet to foot, on their back. Place your baby with their feet at the foot of the cot, on their back, for every sleep.
• Base height. Start on the highest base setting for your back's sake if your baby is not yet pushing up, and drop it as abilities arrive: lower once rolling and pushing up start, lowest position as soon as they can sit.
• Room temperature. The Lullaby Trust advises 16 to 20 degrees C. Cots often live against outside walls or under windows where baskets did not; it is worth checking with a room thermometer rather than assuming.

Some babies move over without noticing. For the ones who protest, the pattern that works is familiarity plus gradualism:

• Start with naps. A few daytime sleeps in the cot before the first full night lets your baby learn the new space when everyone has more patience.
• Keep the sleep cues identical. Same sleeping bag, same routine, same white noise if you use it. The bed is the only variable you want to change.
• Use a sheet that smells familiar. A fitted sheet that has been near you, or on the basket mattress for a night, carries a familiar scent into the new bed. The sheet, not a loose blanket or the old basket mattress itself.
• Move the bed, not the room, if you can. If the cot is replacing the basket in your bedroom, that is one change instead of two. Save the nursery move for a couple of weeks later.
• Expect two or three scrappy nights, not weeks. Most babies settle fast. A baby still fighting the cot after a fortnight is usually telling you about something else: temperature, overtiredness or a sleep regression that coincided with the move.

The move to the cot means a new mattress purchase, and it is the one part of the nursery where The Lullaby Trust's advice is worth quoting directly: "Generally speaking, we recommend buying a new mattress for each baby, although we know this isn't always possible."

If you are reusing a cot mattress, from an older sibling or a second-hand cot, check it against their list before the first night: a fully waterproof cover, no rips or tears, no sagging, still genuinely firm and flat, a fire-resistant label, and a snug fit in your cot with no gaps. A mattress that was stored somewhere damp, or that dents where you press it, has retired.

And whatever you buy, buy the size your cot actually takes. The cot standard BS EN 716-1 allows no more than 3 cm of gap between mattress and frame; the right way to hit that is the exact size, found in about ten seconds in the fitment search.