Is your best friend having their 21st birthday? If yes, you’ve come to the right place! We’ve got a list of the best Instagram captions for you to choose from. Scroll down and pick one that best suits the relationship you share with your bestie.
Instagram Captions for 21st Birthday Letter to Best Friend
• I’m so glad we’re still together…even if I have to buy my own birthday presents
• My Best Friend, I can’t believe that you’re turning 21 and I’m already 26! Here’s to your 21st year and may your life be as wonderful as mine has been because of you.
• Happy 21st birthday to my best friend, who makes me feel like I’m a senior citizen and means more to me than I can ever put into words.💕
• Wishing a wonderful day filled with joy and laughter to my best friend who’s turning 21 on this day.
• Happy 21st birthday to the person who taught me how to be brave, and how to be loved. You’re a goddamn superhero who never stopped fighting.
• Happy Birthday my best friend. If I could put our friendship in a box and give it to you as a gift, I would. You’re the kind of friend that deserves a box full of friendship.
• We’ve been best friends since the first grade when I told everyone you were my girlfriend because we always held hands.
• Happy birthday, friend! You’re one year closer to being old and stuff.
• Here’s to the adventures we’ve been on and all the ones we’re gonna go on. Cheers to my favorite human. ❤️😊
• I’m so lucky to have a drinking buddy like you.
• Good times and laughs, learning, experiences that changed me…🎉#tbt
• Cheers to today and many more. To laughs, smiles, and memories we’ll always cherish.
• What a fun and the unexpected journey we’ve been on. Happy 21st to the best friend, confidant, and wing-gal a girl could ask for.
• You’re not just my best friend. You’re family. Can’t believe it’s our 21st birthday today ☀🎉 #BestFriends21
• Wishing my best friend a happy 21st birthday! Love.
• Best friends can do everything together, and it’s their 22nd birthday to prove it. 🍾🥂 #mybestfriend
• Celebrating your 21st birthday was our favorite present. 🎉
• Today I celebrate turning another year older, and I share a drink with my best friend. ❤️
• Happy birthday, my dearest friend! #BFF
• another year older, another year of friendship.
• It’s your 21st birthday. I can only imagine you’re staying up till midnight, eating the best cake in town, with your best friends.
• Just a little something to say thanks for the great times, good laughs, and the wisdom you’ve shared along the way. Can’t wait to see what’s next! 👯👯
• We made it! Since then, we’ve had so many memorable moments and adventures together. Wishing you all the best for your special day—and always. 🎂💕
• It’s your day and we are ready to celebrate you for 21 years. We want to thank you for shining so bright, always.
• Friendship cannot be defined, it’s something beyond all words,
• Happy 21st to my best friend. I’m grateful that you’re a part of my life. Here’s to another year of memories ahead.
• Turning 21 always feels like a milestone. For us, we’re proud to have grown up with our friends through the years. Happy Birthday, Friend!
• I have always believed that best friends are people who make you laugh and feel good about yourself, people who make you celebrate every single day. Happy birthday, friend!😍
• You are my bestie. I am so glad to have you in my life. Happy Birthday!
• Happy birthday to my best friend. You’ve always been there for me, even on those nights you didn’t want to be.
• I’ll be the first to admit that I’m bad at keeping in touch but you’re never too busy for those who keep your heart
• This is your 21st? Let’s celebrate—with a round of drinks
• How do we keep our friendship so strong? I don’t know, but I’m sure glad we do! 💕
• Sending you love and peace as you enter your new chapter and celebrate what hopefully will be the best year yet.
• I miss you, buddy. But here’s to 21 more years of friendship.
• A love letter to my best friend. Happy birthday, @bestfriendgoals. I can’t wait to see what you have in store for us next year!
• Hey bro! 21st is always better than 20th (just saying). It was a blast partying with you last night. Here’s to the next 21 years of friendship! *Pound It* #21birthday #21Bday
• Dear bestie, I’m so grateful for you. Here’s to the next 21 years of friendship. 🍻
• Grab your squad and get ready for a weekend of relaxation and celebration, because Sunday is your day. Happy 21st birthday!!!
• Turning 21 is one of the greatest things in life. You get to officially drink, drive and vote for the president. I’m super proud of you, my friend 😎 .
• Coming of age and growing up with you has been the most rewarding experience of my life. I wouldn’t change a thing about it. Happy birthday, amiga. 🥰 #foreverfriend
• Looking back on our friendship and all the years we’ve spent together, I can confidently say our story doesn’t have an end. Happy birthday to the sister of my heart.
• My best friend since childhood, are you ready to party?
• The weekend is officially underway and I’m looking forward to a cold one (or 6) with you.
• 21 years with you feels like 21 seconds. Here’s to the next 21 years of never wearing matching socks.
• I’m not sure when it happened, but at some point, we grew up, and I’m happy for it. We’re almost old enough to drink legally
Captions for 21st Birthday Letter to Best Friend
• You’re the best. Wish you a happy 21st birthday, friend. 🎉XX
• My best friend and go-to person, you’re turning 21 years young, but you’ve got the heart of a wise old soul. Cheers, friend! 🎂
• We’ve been BFFs since we were 18… I couldn’t have asked for a better friend and partner in crime to overshare with 😂💗 #21versary
• Happy 21st birthday, my dearest bestie. I couldn’t have asked for a better friend, sister, or co-worker over the last 20 years.
• Remember when you were so excited for your 21st birthday that you wrote a letter to your 18-year-old self? I do.
• I’ve never met someone so real, a true best friend. I’m excited to spend the rest of my life with you, no matter what it holds.
• Wishing you a happy birthday. Here’s to your next 21 and all the adventures that come with it.
• I’m not sure 21 is where I thought I’d be, but I’m pretty happy to be here.
• Twenty-one years, and we’re still doing the same thing. Going out, getting drunk, and spending a ton of money on each other.
• Today we are turning 21. We are legally adults now. Got to love the newfound freedom!
• It’s your time. Congratulations here’s to you!
• Tonight we’re going to a party like it’s my 21st birthday.
• Celebrating with you makes every birthday the best one.
• Happy 21st! Life’s too short to not be silly with your best friend. Here’s to friendship, mine and yours.
• Let the next seven years be even better than the last. Best friends forever, 21! #yourenotalonely
• Here’s to many more years of adventures, short skirts, and cheesy jokes. 😍 #21stbirthday
• When you realize that the party’s never gonna end—you’re the only one who hasn’t grown up. Happy 21st birthday, dearest friend!
• Happy 21st birthday to my bestie. Here’s to many more relaxing nights of drinking cheap wine by a bonfire with our friends and eating the food we don’t really need.
• Happy birthday to my best friend and party of one. 🎈🎉
• When I think about you, my only regret is that you aren’t here to experience all the things that I have. 😮
• You’re the only one who will always catch me when I fall and the only one who doesn’t judge when I put my feet up on the table. Cheers, to our next 21 years of friendship.
• You’re about to be 21 so you are officially old and over. Congrats?
• Happy Birthday! Friends like you are hard to find. May it never takes a village, but instead to always be each others’ person
• Pour some out for the nights we don’t remember and the shots we can’t forget 🍻
• A photo of a best friend and each other on their 21st birthday is a gift in itself. It’s an Instagram caption that captivates people, putting the world on pause for a moment.
• Slumping into my adulthood is underrated. If you are looking for birthday captions for best friends, try these funny and cute templates.
• I can’t believe it’s your 21st birthday 🎉. You’ve been my best friend for so long, I can’t imagine not knowing you. 😊
• 21 years young, guys. You don’t know how lucky you are to be spending your 21st birthday with me.
• Happy birthday to my best friend, the person who made me want to be a better person, the funniest girl I know, and the only one who will ever understand me.
• You’ve gone from best friend to family over the years you’ve shared with me! Happy Birthday
• You’re not just my “best friend” but also my family and the sister I never had. Happy birthday to you, dear!
• You’ve been my friend for over half your life, you’ve given me the gift of new relationships, and you give me immeasurable amounts of joy. I love you, and I’m so excited to celebrate with you.
• My heart is your oyster. Happy birthday, bestie! Have a wonderful year. 😘
• You are only 21 once, but you can be immature forever
• I’m so glad you’re in my life. I can’t wait to see where we go tomorrow.
• Make a Wish, Blow out the Candles. Here’s to 21 years of friendship and so many more to come. Cheers to you, buddy!
• Hey 👏🏻👏🏻👏🏻, it’s not like I’m writing a letter to you on my 21st birthday, but I’m doing it anyway cuz I love you and that’s what best friends do. Happy New Year.
• There’s no one I would rather spend my 21st birthday with than you. You’re my best friend and one of the most important people in my life and I’m so blessed to have you in it.
• You’re turning 21. You’re so mature and classy, you don’t even act your actual age.
• Dear @carlita.babe, thank you for always supporting me. I’m so glad we are celebrating this together with our close friends and family.
• Happy birthday to my best friend. Here’s to another 10 years of memories, 2 years of friendship bracelets, and 1 year of tough love.
• Dear BFF, Here’s to many more days of laughter, tears, and a whole lot of iced coffee ☕ Stay cool for the summer
• Let’s be real, you are the only one that gets me.
• Let’s get wine drunk and watch the sunrise over brunch, which I’m going to make you.
• You’re the glass of wine in my day, the reason I get up in the morning, and the push that gets me through the day. Happy birthday!
Quotes for 21st Birthday Letter to Best Friend
• Happy 21st birthday, bestie! You have always been there for me since forever and I will forever be here for you too.
• My best friend and I are turning 21 this year. I just want her to know how much she means to me and how much she has helped me over the years.
• How have you been doing? I’m so old now, but we both are. Hope your life is as great as ever. I love you my best friend.
• I’m sure we’d hit up some college parties, but I was ready to settle down. I wanted to go on adventures with you. We’ve grown up so fast! Happy happy birthday, my friend.
• It’s your 21st birthday. I’m so proud of how far you’ve come. You’ve grown into such a beautiful person and friend.
• These 21 candles are for you. You’ve lit my life with love and friendship, the two greatest gifts I’ll ever know 🎂 #bestfriend
• Happy birthday to my best friend – the first one who taught me how to text properly 📩👯
• There aren’t enough words to explain how amazing you are. So instead let me just say: I love you. 💙
• Twenty-one is that special age when you can do anything you want.
• Happy Birthday to my friend and soon to be husband.
• Hey, remember when we were 21? That was a fun year!
• When all else fails, remember that our friendship makes you feel secure, supported, and loved.
• Wish you were here! We’re having the best time celebrating your b-day with a few of our favorite people. Here’s to 21 epic years, babe!
• Can you believe it’s been 21 years! It’s crazy how much we’ve grown, but I swear we were so little the last time I saw you.
• I’ve never been someone who looks back and dwells on the past. I’m always looking forward to what’s happening next, especially this week when you turn 21!
• From sneaking into bars to feeling unstoppable, you’ve always made life so much fun. Happy birthday, bestie. 🎉
• Happy 21st birthday, buddy! Wish we could toast with some Cîroc tonight but since we’re not 21 yet, why don’t you come over and watch me play Destiny?
• Happy birthday, to the best of friends. I’ll be over (with some ice cream) as soon as I can.
• Enjoying the long weekend with my bestie ✌🏼😜
• It’s your 21st birthday today! I can’t believe you are already this old, young.
• It’s your birthday and you’re legally allowed to drink now. Let’s celebrate (and embrace the fact that I’m only one year older than you…
• Thanks to everyone who made it out last night for my birthday. It was a total blast, and I had the best time. Thanks for being you guys, you’re all wonderful!
• Throwback to when we were 21 and definitely not drinking coffee ☕️ #TBT
• You’re celebrating your 21st and you’re my best friend. So that’s pretty cool. 🍾
• 21 is a new beginning 🍾If you’re looking for ideas for those 21st birthday gift, don’t forget the classic ones we all love!
• Happy 21st birthday to my best friend. You’re the yin to my yang and the spice to my clove. Here’s looking at nine more years of friendship, shenanigans, and all around good times. Cheers!
• Here’s a little something to help you celebrate your 21st birthday… We love you and we’ll see you soon.
• At 21, you’re no longer a legal adult, but it hardly matters…21’s too big of a number to worry about anyway.
• Here’s to you and all the lessons you’ve taught me over the past twenty years. Happy 21st birthday, my friend.
• I have never been that kid who even remotely aspired to turn 21. Now that it’s here, I am already making plans for the year 2035.
• So much to celebrate on your twenty first birthday! Here’s to twenty more-filled years of vacations, parties, and road trips. Cheers, my best friend.
• You are such a cool friend, I can’t even begin to tell you how much I appreciate your friendship ☺️
• It’s your 21st birthday and it’s hitting me like . . .
• Happy birthday, buddy. Here’s to many more 🎉
Wishing you a happy birthday, my friend. You are old enough to drink now.
Almost 21! Wow, you’ve grown up so much this past year, I feel like we’re still 17. And I’m not just talking about legal drinking.
Happy birthday, where we started our adventure together, who knew what was about to happen
Happy 21st birthday, @bestfriend_name! Wishing you the best year yet!
Happy 21st birthday to my best friend! Wishing you all the happiness in the world today and always.
Celebrate your 21st birthday with the best person you know—yourself. Congrats, boo
As we begin to turn the page on this chapter of our lives, I just want to say thank you for being my ultimate wingman. Cheers to new adventures!
Best friend, you haven’t aged a day since the days at this pool. #birthdaygirl
Happy birthday to my best friend, greatest cheerleader, and biggest fan. I’m so lucky to share life’s journey with you.
Dear best friend, I wish you all the luck in the world as you enter this new chapter of your life. Your blessings are as numerous as they are perfect for you…
I’m not a big fan of birthdays, but I’m a big fan of you—my friend. Happy 21st!
Another year has gone by and I’m so thankful for the amazing life I have. You’ve been my best friend for 21 years, and I hope we have at least 100 more together
I hope this wknd is as good for you as you are for me. I love you my friendeee. #happybirthday
A few drinks, a lot of laughs, and all that jazz. You know the drill.
We’ve come a long way, baby. We’ve had our ups and downs but we have made it! Here’s to the next 21 years (or 22 if you’re into that sort of thing.)
Happy Birthday old boy! Hope it’s all you want it to be and more.
For my bestie, on her 21st. I love you, girl.
Friends are the family you choose and I’m so lucky I get to celebrate my 21st with you. Here’s to more memories, drinks, and adventure.
We’ve been the best of friends for 21 years, but it feels like we’ve been together forever. Happy Birthday, Jane!
Stay relevant, stay beautiful, and always love the skin you’re in.
The days are getting shorter and the weather is getting cooler. It’s a good reminder to make the most of this time with your friends—especially your best friend.
You don’t always need words to say I’m thinking of you, so have another glass of my favorite Pinot with your favorite gal tonight! Cheers!
Hey buddy, (name) here. I’m off to celebrate my birthday and toast to you for being the best friend ever!
Happy birthday! Thanks for always being there for me and driving me to McDonald’s when I’m drunk.
Best birthday wishes to you. May all your dreams and wishes come true.
Let’s see which one of these I’ve actually done: