Kim Zolciak Continues to Flaunt Her Tiny Waist in Favorite Bikini

The reality star celebrated her 38th birthday on the beach.

Kim Zolciak brought along her favorite bikini for a vacation to celebrate her 38th birthday.

The Don't Be Tardy star's husband Kroy Biermann, who recently donned his own scantily-clad swimwear, took the birthday girl on a sunny vacation, and she, of course, had to share some pics of the getaway with her two million Instagram followers.

WATCH: Kim Zolciak Secretly Snaps Pic of Hunky Hubby Kroy Biermann in a Tiny Yellow Speedo

The mother-of-six posted a pic of herself wading in the water wearing a scantily-clad swimsuit. "My hubby surprised me and took me to my fave spot to celebrate my birthday tomorrow," Zolciak captioned the image on Wednesday. "Isn't the ocean magnificent! It looks like a big giant pool."

On Thursday, her actual birthday, the reality star looked back on the past year with a sense of gratitude. "It's my birthday!! I love celebrating. I have so much to celebrate this year and every year here after!" she wrote. "My birthday got REAL special after my stroke/heart surgery. I can't help but reflect back to this last year. I feel so blessed/grateful/thankful to turn 38 today! I have the most incredible husband and children on this planet, the most incredible friends, the most incredible fans THANK YOU #TaurusBaby #Beach #FunInTheSun"

WATCH: Kim Zolciak Flashes Her Incredibly Tiny Waist After Tea Detox -- See the Jaw-Dropping Pic

If Zolciak's bikini looks familiar, it's because this isn't the first time she's posed in the two-piece. Over a month ago, she snapped a selfie in the summer style to show off her tiny waist and praise the detox tea she'd been promoting.

Zolciak also credits waist trainers for helping with her figure. "My husband usually hooks it for me because I like mine pretty tight," Zolciak told ET about her corset. "I get a lot of negative comments -- 'You've gotten too small!' -- [but] how can your waist ever be too small? That's what I'd like to know."