The first signs of puberty in boys and how to spot them
boys with signs of puberty in boys playing guitar

The first signs of puberty in boys and how to spot them

Inside: By looking out for the first signs of puberty in boys, parents can be prepared and start talking to their sons about puberty before their body starts changing.

Recognising the first signs of puberty in boys can be a bit trickier than it can be in girls.

Especially if your son doesn't walk around the house naked anymore.

Girls usually have more obvious signs, like breasts, that can't be hidden under clothing.

Whereas the first sign of puberty in males is usually hidden, and can only be seen under their clothing.

You can read this article to learn more about the signs of puberty in girls

When to expect the first signs of puberty in boys

So when should you expect to see the first signs of puberty in boys?

For boys, puberty usually starts around 2 years later than it does for girls.

So for boys, puberty usually begins around the age of 10 to 12. It can be as early as 9 (yes, that early) or as late as 12-15.

And the changes can take anywhere from 2 to 5 years to be finished.  

Every boy is different and puberty will begin when his body is ready for it. You can’t rush it!

The timing of puberty is influenced by many things – diet, body weight and their environment. The chances are, that if you were an early or  late bloomer, that your son will be as well.

You'll find more information about puberty in my Puberty 101 page.

What are the first signs of puberty in boys

So although the timing of puberty can be different for every boy, the sequence of changes are much more predictable. There is a usual pattern of changes that we can expect to see in boys.

We can expect emotional and physical changes that will prewarn us that puberty is on it’s way.

Emotional signs of puberty in boys

When we think of the emotional signs of puberty in boys, we tend to think of them only happening in girls. But they do happen in boys too, especially in the very beginning, before you start to see the physical changes.

Mood changes can often be the first sign of puberty in males (in females too).

So you may begin to see mood swings,  as his body adapts to the surge of hormones that he is now experiencing. One moment he may be feeling happy and then very angry the next. Boys are as likely as girls, some say even more so, to becoming more upset or angry during the early stage of puberty.  

Some boys also act more impulsively during puberty.

boys with thumb up and down

Parents often complain about boys first becoming moody at around 9 to10.

Physical signs of puberty in boys

Unlike girls, the physical signs of puberty in males are much harder to spot as they are usually hidden under their clothing. And if your son is shy  with being naked, then you will miss some of the early physical signs.

You’ll start to see physical changes anywhere between the ages of 11 to 13, depending on how observant you are or on how much nudity you see in your son. And remember every boy is different – some boys will be earlier or later than their friends. And some may have changes in a slightly different order!

Usually, before anything else, you’ll notice that they have gone up a shoe size or two. So you can expect their feet and hands to have a growth spurt, and for them to suddenly be a lot taller. 

As their feet grow, you might begin to notice smelly feet for the first time (or their feet may be smellier than they normally are). Their body may even begin to smell or pong, especially after they have been outside running around for a while.

The next changes are not so obvious to spot, unless you know what you are looking for.  Their testicles will grow slightly larger, and their scrotum will hang lower, become darker in colour, thinner and be less smooth.

They will begin to grow more hair on their legs and under their arms, in their armpits for the first time. Fine pubic hair begins to grow at the base of the penis and scrotum. These first hairs are usually long and slightly curly. For some boys though, hair growth may not begin until they are over 13.

The penis may have grown a little wider but now, as their testicles continue to grow and their pubic hair begins to become darker, thicker and curlier, their penis will start to change.  Their penis will now begin to grow longer. Erections will also be a lot more common than ever before, often happening when they least expect it.

As their muscles begin to grow larger and their shoulders broader, some boys  may get short-term swelling and tenderness around their nipples ie grow breasts. This usually happens around the age of 12 to 14, and any breast development will usually disappear within a year or two.

Boys will continue to grow taller and wider, with hair growth continuing on their legs and under their arms.

Sometime between the age of 13 to 16, boys will begin to produce sperm. They may begin to have their first wet dreams and ejaculate for the first time when masturbating. For the first time, their voice may also begin to break or crack as their vocal cords change and their voice deepens.

Between 14 to 18, boys will now start to grow facial hair and their skin may become oily with pimples. Chest hair may also begin to grow for some boys, the amount depending on how hairy the other males in their family are.

During all of this boys will continue to grow taller and wider as their muscles develop and grow.

father teaching son to shave

Facial hair is one of the last changes to happen.


There are many fantastic books that can help you to start having those first conversations with your son.

Hair in Funny Places is a great first book for talking about puberty. It is funny and an enjoyable story to read. It is one that you can start reading to your son (or daughter) from about the age of 5 or 6. This then helps to plant the seeds early about the fact that one day his body will begin to change, meaning that he won't find it a big shock when puberty finally arrives.

When it comes to puberty books, there are 3 types.

The first type of books are the  ones that are written for younger boys who are either curious or are starting to show early signs of puberty. These books just talk about puberty and avoid the topic of sex. You can find examples of these puberty books for younger boys here.  

The second type of books are for boys who are a little bit older, and these books are beginning to talk about sex. You can find examples of these types of puberty books for older boys here.

The third type of books are for older boys who are already showing signs of puberty, are teenagers and curious about sex. These books are almost sex manuals and they provide a lot of information about sex. You can find examples of these types of puberty books for teenage boys here.

If you're unsure about how to start talking to your son, Puberty Boy - How to talk about puberty and sex with your tween boy, will help you to get started. It is a straightforward common-sense guide that doesn't just tell you what to talk about, but how to start saying it.

So, these are the signs of puberty in boys that you should be looking out for, and are the ones that signal that it is time to start talking.

With boys it can sometimes be harder to spot these changes. especially if they don't walk around the house naked! But once you begin  to see these signs of puberty in boys, you'll know that puberty is well and truly, on it's way.

And hopefully, you'll start talking before too many more changes will have happened.


My mission is to create resources that will help you to naturally talk to your kids about sex, all while respecting your personal values.

Which means that inside this website, you'll find lots of resources to help you with talking to your child about puberty.

My Puberty 101 page includes all of the information on puberty. You'll find lots of different blogposts to help with talking to your child about growing up.

You'll find videos about puberty in my Sex Education Videos resource page that you can watch with your child or to learn more about puberty yourself.

You’ll also find an extensive range of children’s books on puberty, for kids of all ages. 

If you get stuck and feel that you need some extra support with talking to your child about puberty, then my book, Boy Puberty – How to talk about puberty and sex with your tween boy or Girl Puberty - How to talk about puberty and sex with your tween girl, may be helpful. It's a straightforward common sense guide that will help you to start having honest conversations that will guide your child through puberty, and strengthen your relationship without feeling embarrassed, awkward or nervous.

If you need some help with explaining sexual intercourse to your child, then How to Talk to Kids About Sex will help you explain sex to your child in a way they will understand. It breaks it down into simple steps that  take the stress out of explaining!

If you want a printed book to hold in your hands, then the  The Sex Education Answer Book will give you age-specific answers to the most common questions kid's ask parents about sex. Which means you don't need to worry about finding a child-friendly explanation that your child understands. 

If you want the answers to questions about a lot more than just sex, then Sex Ed Quickies is your best option. It has answers to 300+ questions  that kids commonly ask parents,  including how babies are made, sexual intercourse, body parts, puberty, relationships, pregnancy, birth, masturbation, sexual diversity, gender, pornography, STIs, contraception and much more.

infographic of the signs of puberty in boys infographic

About the Author Cath Hakanson

I'm Cath, a sex educator living in Australia with my husband and 2 kids. I help parents to talk about sex (with less cringe and more confidence) and empower their child to make smart sexual decisions. To find a better way to talk about sex, you can join my community of parents and visit my shop for helpful resources.

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