9-12 Month Baby Development: Key Milestones and Changes

Between 9 and 12 months, your baby may become increasingly mobile, communicative and determined to explore. Sitting can become more confident, hands become more precise, babbling may sound increasingly speech-like and some babies begin pulling themselves up or moving while holding onto furniture.

There is a wide range of development during these months. A baby who has just turned 9 months can look very different developmentally from a baby approaching their first birthday. Some babies crawl, some move in other ways, and some may take independent steps before 12 months while others will do so later.

Developmental milestones are useful reference points, not a schedule your baby needs to complete. What matters most is the broader pattern of how your baby is developing across movement, communication, learning and social interaction.

What changes between 9 and 12 months?

The final few months of the first year can bring rapid changes in how your baby interacts with their surroundings.

At 9 months, the US Centers for Disease Control and Prevention lists milestones such as sitting without support, moving objects from one hand to the other, making repeated sounds and looking when their name is called.

By 12 months, milestones include pulling up to stand, walking while holding onto furniture, waving goodbye, looking for hidden objects and beginning to use a special name such as “mama” or “dada” for a parent or caregiver.

Between those points, your baby may spend a great deal of time practising.

You may notice changes in:

sitting and moving around
pulling up and standing with support
hand and finger control
babbling and early communication
gestures such as waving
understanding familiar words
playing simple interactive games
searching for objects
responding strongly to familiar people

Not every baby will develop these skills in the same order.

By around 9 months, many babies are becoming increasingly confident in a sitting position.

The CDC lists getting into a sitting position and sitting without support among its 9-month physical milestones. Moving an object from one hand to the other is another skill commonly seen at this stage.

Communication is becoming more varied too. Your baby may make long strings of repeated sounds such as “mamamama” or “bababababa”. They may lift their arms when they want to be picked up and look towards you when you call their name.

Socially, your baby may react when you leave and enjoy interactive games such as peekaboo. Some babies also become shy, clingy or cautious around unfamiliar people.

These responses can vary with personality and circumstances. Your baby does not have to react to every person or situation in the same way.

Around 10 months: exploring and communicating

There is no separate official CDC milestone checklist for 10 months, so this period is best understood as a time when skills between the 9-month and 12-month checkpoints continue developing.

You may notice your baby becoming more deliberate about getting your attention. Communication can involve sounds, gestures, reaching, facial expressions and body movements.

The NHS recommends combining words with gestures during the 6 to 12 month period. For example, you might wave while saying goodbye or point towards something as you name it.

Your baby may also become increasingly interested in objects and what they can do with them. Putting things into containers, taking them out again, dropping objects and searching for something that has disappeared can all become fascinating.

Repeated play can feel very simple to an adult, but babies are learning about actions, reactions and the behaviour of objects.

Around 11 months: practising independence

At 11 months, many babies are busy strengthening and refining skills rather than suddenly acquiring a completely new set.

Movement may become more confident. Your baby might move around the floor in their preferred way, pull themselves into different positions or practise standing while supported.

Some babies move while holding onto furniture. Others may still be concentrating on earlier physical skills.

Their hands are becoming more useful too. By 12 months, the CDC lists putting an object into a container and picking up small pieces of food between the thumb and first finger among common milestones.

Communication may also become increasingly intentional. Your baby might use familiar gestures, copy sounds or respond to simple language used repeatedly in everyday situations.

Keep talking naturally. You do not need to test whether your baby knows particular words.

Around 12 months: approaching the first birthday

By your baby’s first birthday, the difference from the newborn stage can feel enormous.

According to the CDC, social and emotional milestones by 12 months include playing simple games with you, such as pat-a-cake.

Communication milestones include waving goodbye, calling a parent “mama”, “dada” or another special name and understanding “no”, which may be shown by briefly pausing or stopping.

Thinking and learning are developing alongside communication. A 12-month-old may put an object into a container and look for something they saw you hide.

Physical milestones include pulling up to stand and walking while holding onto furniture.

Independent walking is not on the CDC’s 12-month milestone checklist. Some babies take independent steps before or around their first birthday, while others begin later.

A first birthday is a lovely marker of how much your baby has changed, but it is not a deadline for walking, talking or completing a particular set of skills.

Does a baby need to crawl before 12 months?

Crawling is not included as a milestone on either the CDC’s 9-month or 12-month milestone checklists.

Some babies crawl on hands and knees. Others shuffle, roll or find another way to move. The NHS notes that not all babies crawl.

Rather than treating crawling as a required stage, look at your baby’s overall movement and development.

If you have concerns about mobility, including how your baby uses their arms or legs, speak to your health visitor or GP.

Movement from 9 to 12 months

Physical development can become especially noticeable during these months because babies are gaining ways to change position and explore.

A baby who sits confidently may begin working on getting themselves into sitting. Later, pulling to stand and moving while holding onto furniture may appear.

As your baby’s mobility increases, their environment needs to keep up.

The NHS advises making the home safe before babies begin crawling and recommends fitting safety gates to prevent access to stairs once babies are mobile. Medicines, cleaning products and other hazardous items should be kept safely out of reach.

Your baby may discover a new movement before you expect it, so reviewing their surroundings before the next skill appears is sensible.

Communication and early language

Your baby may not be speaking recognisable words yet, but they are learning a great deal about communication.

During the 6 to 12 month period, the NHS recommends talking about things you can both see, using your baby’s name, looking at books together and combining words with gestures.

You can follow your baby’s attention rather than constantly directing it. If they point, reach or stare at something, name it. If they babble to you, respond and give them a moment to answer again.

By 12 months, some babies use a special name for a parent or caregiver and understand “no”, according to the CDC.

These early communication skills develop through ordinary interaction. You do not need flashcards or formal language lessons.

Fine motor skills and learning through play

Hands become increasingly precise towards the end of the first year.

At 9 months, moving objects from one hand to another is among the CDC’s milestones. By 12 months, babies may put objects into containers and pick up small items between their thumb and first finger.

You may notice your baby becoming absorbed in repetitive actions. They might put an object into a container, take it out, drop it and then want to repeat the whole process.

They are also beginning to understand more about objects they cannot immediately see. At 9 months, looking for an object that has dropped out of sight is a CDC milestone. By 12 months, babies may look for something they watched you hide.

Simple games can build on this curiosity. You might partly hide a favourite toy under a cloth or offer a safe container with appropriate objects to put in and remove.

Always choose objects that are safe and suitable for your baby’s age, particularly as babies at this stage may still explore things with their mouth.

Towards the end of the first year, babies can become very clear about who and what they know.

At 9 months, the CDC includes reacting when a caregiver leaves and being shy, clingy or fearful around unfamiliar people among common milestones.

Your baby may want to stay close to you in an unfamiliar situation or take time to warm up to somebody new. There is no need to force immediate interaction.

Familiar games may become increasingly enjoyable because your baby can anticipate what happens next. Peekaboo, clapping games and songs with repeated actions can encourage shared attention and communication.

Your baby’s personality is becoming more visible too. Some babies enthusiastically investigate everything, while others prefer to watch before joining in.

Simple ways to support development from 9 to 12 months

You do not need to create a daily developmental curriculum.

Ordinary play and conversation give babies plenty of opportunities to practise emerging skills.

You can:

talk about things your baby notices
share picture books and name familiar objects
respond to babbling, gestures and facial expressions
use simple gestures alongside words
play peekaboo and other repetitive games
offer safe containers and objects for simple putting-in and taking-out play
provide safe floor space for movement
allow your baby time to practise physical skills at their own pace
follow their interests during play

The NHS emphasises talking, reading, playing and responding to babies during this stage.

There will also be days when your baby is tired, unsettled or simply not interested in an activity. You do not need to make every moment educational.

Your baby’s 9 to 12 month development review

In England, the NHS offers babies a health and development review between 9 and 12 months.

The review covers areas including language and learning, safety, diet and behaviour. It is also an opportunity to talk about anything that is worrying you.

You may be sent an Ages and Stages Questionnaire before the review. The NHS explains that this helps parents and health visitors understand how a baby is developing and identify areas where additional support might be useful.

Try not to think of the review as an exam for you or your baby. Its purpose is to look at development and provide support where needed.

When to get professional advice

Speak to your health visitor, GP or another qualified healthcare professional if you are concerned about your baby’s movement, communication, hearing, vision, social interaction or general development.

The CDC advises parents to act early if a child is not meeting one or more milestones, has lost skills they previously had or if there are other concerns about development. A healthcare professional can discuss whether developmental screening or further assessment would be appropriate.

You can also raise concerns during your baby’s 9 to 12 month NHS development review, but you do not need to wait for that appointment if something is worrying you now.

Milestone guides can show you the broad pattern of typical development. They cannot assess your individual child. If your instincts are telling you to ask a question, it is reasonable to ask it.