When to Flip a Two-Sided Crib Mattress: A Guide for Growing Babies

Your baby grows fast. One day they’re a tiny newborn, and before you know it, they’re pulling up on the crib rails, ready to take on the world. But with all these milestones, there’s one transition that often catches parents off guard: knowing when to flip a two-sided crib mattress.

A two-sided crib mattress is built for both infancy and toddlerhood, with a firm side to support newborn safety and a softer side designed for growing toddlers. Flipping it at the right time is key to balancing comfort and safety. But how do you know when your baby is ready? And is there any harm in flipping too soon?

In this guide, we’ll break down when to flip your two-sided crib mattress, signs your baby is ready and how to make the switch safely. Keep reading to make the big flip with confidence!

A two-sided crib mattress is designed to adapt as your baby grows, offering the right level of support at every stage. One side is extra firm to provide a safe sleep surface for infants, ideally following CPSC and AAP recommendations to help to reduce the risk of suffocation and support proper development.

It’s important for parents to remember that when you have an infant, baby safety always comes first – that means it comes before comfort. Newborns lack the muscle control to move their heads easily, making a firmer sleep surface essential. A mattress that’s too soft can increase the risk of suffocation or make it harder for babies to reposition themselves if needed.

By contrast, toddlers have more mobility and benefit from a mattress that offers cushioning without compromising support. That’s why the other side of a two-sided mattress is slightly softer, giving toddlers a more comfortable surface once they no longer need the same level of firmness.

There’s no universal moment when every baby is ready for the toddler side of a two-sided crib mattress, but most experts recommend making the switch around 12 months. By this age, babies typically have better head and body control, reducing the risk of suffocation that makes a firmer sleep surface necessary in the early months. However, every child develops at their own pace, and flipping too soon can pose safety risks.

The American Academy of Pediatrics (AAP) recommends keeping infants on a firm sleep surface for at least the first year, even if they seem uncomfortable. Most two-sided crib mattresses are designed to be flipped between 12 and 18 months, though some children may be ready earlier while others continue to sleep well on the infant side longer. 

Manufacturer guidelines can provide additional clarity, as many brands specify the ideal age range for flipping. (At Lullaby Earth, we follow expert recommendations and say no earlier than 12 months is your safest bet!)

Every baby develops at their own pace, which means there’s no exact day when flipping the crib mattress becomes necessary. Age is a helpful guideline, but the best way to determine if it’s time is by watching for physical and behavioral signs that your baby is ready for a softer sleep surface. Some key indicators include:

• Increased mobility during sleep. If your baby can sit up, pull to stand or move around the crib easily, they likely have the strength and control needed for a less firm surface.
• Consistently sleeping through the night. Frequent wake-ups or restlessness may be due to factors other than mattress firmness, but a child who sleeps well overall may benefit from the added comfort of the toddler side.
• Visible discomfort on the infant side. If your baby tosses and turns more than usual or seems unsettled when lying down, they might be ready for a bit more cushioning.
• Outgrowing the need for a firm surface. The firmer infant side supports spinal development in younger babies, but as your child grows and their body strengthens, the extra firmness becomes less necessary.

If there’s uncertainty, it’s okay to wait a little longer – your baby’s comfort matters, but their well-being is the top priority.

Once your baby is ready for the toddler side, flipping the mattress is a straightforward process. 

• Remove all bedding.
• Check the mattress labels.
• Flip the mattress to the toddler side.
• Inspect the mattress for wear.
• Ensure a snug fit in the crib.
• Reassemble the crib with proper bedding. 

Remember! Avoid loose bedding, pillows or other soft items that could pose a safety risk.

Marking the date of the flip in your phone or on a calendar can help you keep track of when the switch was made. With everything set up correctly, your toddler will have a comfortable and safe sleep space as they continue to grow.

Parents often have questions about when and how to flip a crib mattress, especially when balancing safety and comfort. Below are answers to some of the most common concerns.

While every baby is different, most experts recommend waiting until at least 12 months before flipping to the toddler side. Even if your baby seems uncomfortable, it's safer to wait until they have better mobility and strength.  If they appear restless, consider adjusting other factors to create a sleep-inducing nursery like room temperature, sleepwear or crib sheet material before flipping the mattress too soon.

Babies can be restless for many reasons, and discomfort on the infant side doesn’t always mean it’s time to flip. First, check for other possible issues. Are they teething, going through a sleep regression or experiencing a growth spurt? If they still fight sleep, you can try adding a breathable mattress pad for a slight cushion while maintaining a safe level of firmness. 

Most two-sided crib mattresses come with clear labels to indicate the infant and toddler sides. If you don’t see any markings, check the manufacturer’s instructions. In some cases, the difference is noticeable – running your hand over both sides should help you tell them apart if the labels aren’t visible.

Some parents choose to rotate the mattress every few months to even out wear, but this depends on the mattress type. If you notice any uneven spots or indentations, rotating the mattress can help distribute weight more evenly and extend its lifespan.

Flipping a two-sided crib mattress is a small but important milestone in your baby’s sleep journey. Timing it right ensures both safety and comfort as they grow. If in doubt, follow manufacturer guidelines and watch for signs that your little one is ready. A well-rested baby is a happy baby – and a happy baby means better sleep for everyone!

Wondering when it’s time for the next big switch? We’ve also got tips to help you confidently transition from a crib mattress to a big kid bed.