18th Birthday Card Messages: What To Write

Published on: April 11, 2024

It’s the big 18, finally adulthood! The special birthday where someone will be excited about everything legal they can now do and all the fuss we’re sure they’ll be getting. We know that writing their card could be daunting if you’re lacking inspiration, but it doesn’t have to be. We believe cards just require a bit of extra love. As turning 18 is such a huge milestone, we’ve come up with a few helpful suggestions for what to write inside an 18th card.

Sentimental 18th messages

Maybe you’d like to send a personal, sentimental message? We have a few suggestions for you:

  • Happy 18th! You have so much potential, and I can’t wait to see all the amazing things you’ll achieve.
  • You’ll smash your journey through adulthood.
  • Let’s celebrate everything you’ve become and look into the exciting future you have ahead.
  • Be adventurous, try new things and experience everything! Have an awesome journey through your adult life.
  • Happy 18th! Someone as wonderful as you deserves the best birthday in the world.
  • Happy birthday! You make everyone around you happy, now it’s your time to do everything that makes you happy.
  • You’re finally 18, so today is your day. Let’s celebrate another amazing year of you! 
  • Sending all my love to you on your special day, you’ll be a fabulous adult. Happy 18th birthday!

Funny 18th messages 

They may be growing up into an adult now, but that doesn’t mean you need to act mature too! So, here’s some funny messages to write in their funny card:

  • Apparently, you’re an adult now. I don’t buy it.
  • Adulthood just means you look older but still feel like a child…I think you’ll be great!
  • If you don’t do wild things while you’re young, you’ll have nothing to smile about when you’re old. Happy 18th birthday!
  • Happy 18th birthday! Now you’re an adult you can do everything legally you were doing illegally before…
  • Now you’re an adult you’ll soon start lying about your age in the opposite direction.
  • Being an adult is just like being a child, except there’s more hard work and lots of depression.
  • When you’re 18 you’ll make mistakes, you’ll be old enough to regret them but young enough to make some more. Have fun!
  • You’ve spent the last 18 years being a problematic, now you’re legal to drink I expect that’ll carry on. Happy 18th!
  • Happy 18th birthday! We’ve got no hope now you’re the responsible adult of the group.

Inspirational 18th messages

Turning an adult will scare the best of us so show them some support. Inspire and uplift your loved one on their 18th with these inspirational messages:

  • Even though you’re now an adult; you’re still young. So don’t let life pass you by without living it to the fullest!
  • Now you’re another year older, the new year can bring a fresh start with an exciting future.
  • With 18 comes freedom and responsibility, so have fun and try and be responsible.
  • Happy 18th birthday! Wishing you another year filled with success and happiness.
  • Today is the start of a bright future ahead for you, so make sure it’s filled with love and laughter.
  • Now you’re officially an adult you can turn your dreams into reality! Go get that dream job, dream car and dream house you’ve always wanted.
  • Happy 18th birthday. Live life to the fullest & start with today!
  • I wish you good health, happiness and a fab adulthood ahead.

Messages to a friend

Is it a friend’s 18th? Whether they’re a best friend since childhood or even a mere acquaintance, we think they deserve a great message in their card. For fun, light-hearted messages for a friend’s 18th…we’ve got you covered:

  • Cheers to 18 years of fun, friendship and lots of laughter together. 
  • Can you believe you’re an actual “adult” now? I can’t! Happy birthday!
  • Older, wiser and hotter than ever! Let’s make your birthday as amazing as you are! 
  • Happy 18th! Let’s go out and do everything legally we did illegally before.
  • I hope you have as much fun on your birthday as we have together.
  • I can’t believe you’re 18! We’ve grown up as kids together and now we can be adults together. 
  • Happy 18th! I couldn’t have grown up with anyone better, you’ll always be my best friend.
  • Now you’re finally 18 and can legally drink, I promise to hold your hair back any time you need.

Messages to a Son/ Daughter

They’re finally grown up and ready to flee the nest! To all the proud Mums and Dads, we’ve got the perfect messages for your sons or daughters 18th:

  • It feels like only yesterday you were a child! 
  • Now you’re 18 we won’t be paying your phone bill, happy birthday.
  • Happy Birthday. Just so you know you’re cut off. Now you’ll have the freedom to do everything but the money to do nothing. Good luck!
  • Now you’re an ‘adult’ it’s finally time to put everything you’ve learnt from your past mistakes into action.
  • You’ve already been such an amazing Son/Daughter, we know you’ll be an amazing adult.
  • You may be an adult now, but as our Son/Daughter you’re still our kid!
  • To a special Son/Daughter, happy 18th. You get your intelligence and good looks from me, and your foul mouth from your Dad/Mum.
  • Happy 18th birthday to my Son/Daughter. You’re old enough to do what you want, but whilst you’re under my roof it’s bed by 10 and still no to parties. Have fun!

Messages to a Granddaughter/ Grandson

Watching your grandkids go from babies to adults goes past in a flash. Here are a few suggestions of heartfelt messages to write in their card wishing them the best in their adult future:

  • Happy 18th birthday! We’ve had the pleasure of seeing you grow up from a baby, so do us proud and be the amazing adult we know you will be.
  • To my amazing Granddaughter/ Grandson, we can’t believe what a lovely young man/woman you’ve grown up to be. Happy 18th birthday!
  • As you go into adulthood don’t forget your family is with you every step of the way. Happy 18th birthday!
  • We couldn’t feel older now you are officially an ‘adult’, it was only yesterday we held you as a tiny child.
  • We are so proud of how strong and independent you have become, happy birthday to you Granddaughter/ Grandson.
  • Wishing you a very happy 18th birthday! From the best Grandad/Grandma.
  • Happy birthday Granddaughter/Grandson, watching you grow into the amazing person that you are today has been a joy.
  • To my Granddaughter/Grandson on their 18th, I wish you a day filled with happiness and laughter.

So now you’re almost sorted. No need to stress about what to write in their card, but are you sure the card you’ve got will cut it? If not, look no further, we have all different types of 18th birthday cards to suit any individual – we’ve even got 18th birthday presents too!

Whether you’re looking to really touch their heart with a sentimental or inspirational card, or perhaps make them giggle with something funny, we have the card you’re searching for. Find our whole range of 18th birthday cards on our website!