Smiling baby with rosy cheeks held by his mother

Do Babies Breathe Through Their Nose or Mouth?

Updated October 2026 · Reviewed for safety and accuracy by the Lively Living team

New parents often find themselves watching their baby's every breath and wondering if they're breathing properly. It's completely natural to be curious about your little one's breathing, particularly whether babies breathe through their nose or mouth. In this post, we look at how infant breathing works, why a clear nose matters so much, and simple ways to keep your baby comfortable when they're congested.

How babies breathe

As a parent, have you ever wondered how your little one breathes? It's a question that crossed my mind countless times in those early days, when I'd watch my baby sleep and check that their tiny chest was rising and falling steadily. Here's the fascinating part: young babies are natural nose breathers. Unlike adults, who switch easily between nose and mouth, newborns breathe mainly through their nose for the first few months of life. They can breathe through their mouth when they cry or when their nose is very blocked, but nose breathing is their default.

Why babies breathe through their nose

It comes down to their unique anatomy. Newborns have a large tongue relative to the size of their mouth, and their soft palate and epiglottis sit close together, which makes breathing through the mouth harder work.

There's a clever reason for this. When a baby is feeding, their mouth is busy with the breast or bottle. Breathing through the nose lets them feed and breathe at the same time. That's also why a blocked nose can make feeding so frustrating for little ones. Our guide to clearing a congested baby's nose for feeding has practical tips.

Baby sleeping peacefully on their back

Benefits of nasal breathing in babies

The nose filters, warms and moistens the air

The nose is a built-in filter. Tiny hairs and mucus inside the nose trap dust and other particles before they reach the lungs. The nasal passages also warm and moisten the air on its way in, so the delicate airways don't dry out.

Nose breathing and development

Nose breathing is also thought to play a part in the healthy development of the face, jaw and airways. Ongoing mouth breathing in older babies and children has been linked with issues such as a narrower palate, crowded teeth and disturbed sleep, so it's worth mentioning to your GP if you notice your child breathing through their mouth most of the time.

Why babies may breathe through their mouth

A blocked nose

The most common reason is simply a blocked nose. During a cold, or when the nose is irritated by dust or dry air, the nasal passages can fill with mucus and swell, leaving your baby little choice but to breathe through their mouth.

Respiratory infections

Infections such as RSV can make breathing harder work for babies. Mouth breathing during an illness is usually temporary, but if it continues after your baby has recovered, it's a good idea to have them checked by your GP.

Structural causes

In rare cases, a baby may be born with a narrowing or blockage in the nasal passages, such as choanal atresia, or with differences in the jaw and airway. If your baby consistently breathes through their mouth, mention it to your GP or child health nurse so they can look into the cause.

How to keep your baby's nose clear

Because young babies rely on their nose, a little help clearing it can make a big difference to feeding and sleep.

Step 1. Saline drops or spray

Saline is sterile salt water that loosens and thins mucus. Lay your baby on their back, put a few drops into each nostril and wait a minute or two. Saline sprays work in a similar way and are often easier with older babies.

Step 2. A nasal aspirator

Once the mucus has loosened, a nasal aspirator (sometimes called a "snot sucker") gently removes it. Our rechargeable nasal aspirator uses gentle suction at the touch of a button, so you can clear your baby's nose before feeds and sleep. Wash it in warm, soapy water after each use and let it air dry. Our step-by-step nasal aspirator guide shows you exactly how to use one.

Step 3. Add moisture to the air

Dry air can irritate little noses. Many parents use a cool mist humidifier in the nursery to keep the air comfortable. Our award-winning Aroma-Snooze Plus combines a cool mist humidifier with soothing sounds and a soft red night light. Read more in does a humidifier help with a snotty nose?

A note on essential oils: avoid essential oils altogether for babies under 3 months. For older babies, check with your GP or child health nurse first, and if you do diffuse, choose a gentle oil such as Eucalyptus radiata or a blend made for children, use just 1 to 2 drops in a well-ventilated room, and keep the mist away from your baby's face. Our guide to essential oils for kids covers safe use by age.

Step 4. Keep sleep safe

Even when your baby is congested, always put them to sleep on their back on a firm, flat mattress, with no pillows, wedges or raised cot. Red Nose has the full safe sleeping guidelines.

When to seek medical advice

Occasional mouth breathing during a cold is usually nothing to worry about. See your GP if your baby:

breathes through their mouth most of the time, even when they're well
has trouble feeding or fewer wet nappies than usual
has noisy breathing or snores regularly
is under 3 months and has a temperature of 38°C or more

Call 000 if your baby is struggling to breathe, has pauses in their breathing, or has blue or pale lips. Trust your instincts: if something doesn't seem right, seek help. You can also call healthdirect on 1800 022 222 any time for advice from a registered nurse.

Frequently asked questions

Is it okay to let baby sleep with a stuffy nose?

Yes. Keep your baby on their back on a firm, flat mattress, as Red Nose advises against raising the head of the cot. Before sleep, saline drops and a nasal aspirator can clear their nose, and a cool mist humidifier keeps the air comfortable.

Do babies breathe through their nose or mouth in the womb?

Neither. Babies don't breathe air in the womb; they get oxygen through the placenta and umbilical cord.

Do babies breathe when they swallow?

Young babies are very good at coordinating sucking, swallowing and breathing, which is one reason a clear nose matters so much during feeds.

When do babies start breathing through their mouth?

Babies gradually become more comfortable breathing through their mouth over the first few months, as their mouth and throat grow.

The bottom line

Babies are natural nose breathers, so a clear nose makes a real difference to how well they feed and sleep. With saline, a gentle nasal aspirator and comfortable, moist air, you can keep your little one breathing easy, and you'll know when it's time to call the GP.