Preparing Your Puppy for Adulthood
When does my puppy become an adult dog?
When should I switch from puppy to adult food?
Should I book a vet check-up for my dog?
Behaviour, training and life skills
Exercise and sleep needs
Insurance and microchipping
Your 12-Month Puppy Checklist
A note from our vets to you
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Preparing Your Puppy for Adulthood
Well, you made it. A year ago, you brought home a tiny, chaotic bundle of fur who chewed your shoes, woke you up at 3 am, and somehow still managed to steal your heart completely. Now, here you are, the proud owner of an almost-grown-up dog!
Over the past 11 months, we've covered a lot of ground: teething, toilet training, parasites, nutrition, grooming, socialisation, and everything in between. This final blog in the series is all about what happens next. Because there's still plenty to think about as your dog transitions from puppyhood to an adult.
Here’s a simple, practical guide to what to expect and how to support your dog at this exciting age.
When does my puppy become an adult dog?
This depends on your dog’s breed. Small breeds mature much faster than larger breeds. Here, we use the term “adult” to mean physical maturity (being fully grown), though emotional maturity may take longer.
Small breeds (e.g., Chihuahuas or Jack Russells): around 12 months old
Medium breeds (e.g., Spaniels or Border Collies): 12–15 months old
Large and giant breeds (e.g., Golden Retrievers or Great Danes): 18–24 months old
When should I switch from puppy to adult food?
When your dog reaches adulthood, it’s time to transition from puppy to adult food. Puppy food is specially formulated with higher calories and extra minerals to support growth. Once your dog is fully grown, these are no longer needed and could even contribute to weight gain.
It’s important to switch gradually, as sudden changes can upset your dog’s tummy:
Days 1–3: 75% puppy food, 25% adult food
Days 4–6: 50/50 mix
Days 7–9: 25% puppy food, 75% adult food
Day 10 onwards: 100% adult food
Vet tip: Keep a close eye on your dog’s weight and body condition during the transition and afterwards. You may need to adjust portion sizes slightly.
If you’re unsure when to start the switch or which adult food is best for your dog, our online vets are here to help.
Should I book a vet check-up for my dog?
This is a perfect time for a check-up with your vet, especially if your dog hasn’t been seen since their puppy vaccinations. Even if they seem healthy, regular vet visits are one of the most valuable ways to keep your dog well. Routine visits help your vet understand what’s normal for your dog, so that it’s easier to spot subtle changes down the line. Remember, dogs age much faster than we do.
Behaviour, training and life skills
Dogs continue developing mentally well into their second year, and without continued stimulation and reinforcement, behaviours can start to slip. A well-exercised brain is just as important as a well-exercised body! Boredom or frustration can lead to anxiety and destructive behaviour.
Social maturity starts around this age. This means dogs can push boundaries, and you might notice a regression in their behaviour and training. For example, being more distracted on walks, and not listening. Going back to basics with training can help. Practising basic commands such as sit, stay, watch me, and recall with high-value treats can help.
Keep their minds engaged:
Continue gentle, positive exposure to new environments and people. You might notice your dog becomes more selective with who they want to be friends with.
Consider a dog sport or activity suited to their breed (such as agility or scent work).
Keep regular training sessions going, and reinforce basic commands. Your dog's attention span should be better at this age, but they will also be more independent.
Continue using lick mats, puzzle toys and other mental enrichment games
Exercise and sleep needs
At this age, most dogs are ready for more exercise, but it’s important to be careful, as they can still be prone to injuries. Activities like swimming or gentle jogging are great ways to keep your dog fit and build muscle while maintaining a healthy body condition. But have a chat with your vet before you tackle those mountain hikes or marathon runs to make sure your dog is ready (especially for larger breeds!)
Sleep is just as important at this stage. Most adult dogs need around 12 to 14 hours of rest each day, though this can vary depending on their breed and how active they are. A well-rested dog is a happy, healthy dog!
Insurance and microchipping
If you haven't already, make sure your dog is microchipped. This is a legal requirement in the UK and many other countries, and it’s a vital safety net if they ever go missing. Make sure that your contact details on the microchip database are up to date.
Now is also a good moment to review your pet insurance policy. Make sure you have the right level of cover, particularly for any breed-specific conditions your dog may be predisposed to.
Your 12-Month Puppy Checklist
Book an annual health check with your vet
Don’t forget the parasite preventatives - especially fleas, ticks and worms
Plan the puppy to adult food switch
Discuss neutering if not done yet
Continue daily tooth brushing
Check paws, ears, eyes and skin daily for any abnormalities
Keep up regular exercise and mental enrichment
Make sure they are getting enough rest
A note from our vets to you
Getting a puppy through their first year is no small feat. You've navigated sleepless nights, chewed furniture, vet trips, vaccinations, training classes, and about a thousand questions about what is normal and what isn’t. You should feel genuinely proud.
The bond you build with your pup in this first year is the foundation for everything that comes after. Dogs who are well socialised, consistently trained, properly fed, and regularly seen by a vet live the happiest lives and bring the most joy to the families who love them.
Here's to many more years together.
