This post contains affiliate links. Visit our Privacy Policy for more information.

Looking for a fun and adorable way to dress up your little one? This free Crochet Mermaid Tail pattern for babies is the perfect choice! This charming pattern features a whimsical mermaid tail design that’s sure to make a splash. The pattern is easy to follow, making it a great project for crocheters of all levels, and is written specifically for baby sizes.
Whether you’re looking to create a fun photo prop or a cozy blanket for your little one to snuggle up in, this mermaid tail pattern is the perfect choice. You can customize it with your own choice of colors and yarns to create a truly unique and personalized look.
And don’t worry if you’re new to crochet – this pattern includes detailed instructions and helpful tips to guide you through each step of the process. You’ll be a crochet pro in no time!
So grab your crochet hook and dive into the world of mermaids with this free crochet mermaid tail pattern. Your little one is sure to love this adorable and cozy accessory!
Be sure to check out my many other free crochet patterns for babies and children!
While crochet costumes can be adorable and fun for babies to wear, it is important to never leave a baby unattended while wearing any type of costume, including those made from crochet. Always use caution and common sense when dressing up your baby.

Etsy Shop
This pattern is also available as an ad-free PDF pattern in my Etsy Shop.
Project Materials
Skill Level
Advanced Beginner. Projects may include simple stitch patterns, color work, and/or shaping.
Crochet Mermaid Tail Size Chart
Size | Chest | Waist | Hips |
0-3 Months | 16 inches | 18 inches | 19 inches |
3-6 Months | 17 inches | 19 inches | 20 inches |
Gauge
12 tc sts and 6 rows= 4″
Pattern Notes
- This pattern is written for two lengths: waist to fin length and chest to fin length.
- This pattern starts with a magic circle (also known as a magic ring or adjustable ring). If you are a beginner crocheter, check out my magic circle tutorial.
- Leave a long yarn tail for weaving in when you make your magic circle.
- The beginning of each round starts with a chain. This chain does not count as your first stitch.
- At the end of each round, you’ll join your yarn with a slip stitch (sl st) to the first stitch made in that round.
- You are crocheting in the round.
- Mermaid tail is worked from the bottom up to the waist.
- Instructions between two asterisks (*) should be repeated for the remainder of the round.
- For the headband, go to my Starfish Appliqué Pattern.
- If you prefer to purchase a printable copy of this pattern, visit the listing in my Etsy Shop.
Abbreviations
- ch = chain
- chs = chains
- st = stitch
- sts = stitches
- rnd = round
- rnds = rounds
- tc = treble crochet
- tc inc =treble crochet increase
- sc = single crochet
- dc = double crochet
Crochet Stitches & Techniques
Chain (ch)
- Start by making a slip knot on your crochet hook.
- Hold the hook in your right hand (or left hand, if you’re left-handed) and the yarn in your left hand. With the hook, catch the yarn and pull it through the loop on the hook. This creates one chain stitch.
- Continue making chain stitches by repeating step 2.
Slip Stitch (sl st)
- Insert hook into next stitch.
- Yarn over and pull through the stitch and through the loop on your hook.
Single Crochet (sc)
- Insert hook in next stitch.
- Yarn over and pull up a loop. You will have 2 loops on your hook.
- Yarn over and pull through both loops.
Double Crochet (dc)
- Yarn over & insert hook in next stitch.
- Yarn over and pull up a loop. You will have 3 loops on your hook.
- Yarn over and pull through 2 loops. You will have 2 loops on your hook.
- Yarn over and pull through remaining 2 loops on your hook.
Treble Crochet (tc)
- Yarn over twice & insert hook in next stitch.
- Yarn over & pull up a loop. You will have 4 loops on the hook.
- Yarn over and pull through 2 loops. You will have 3 loops on your hook.
- Yarn over and pull through 2 loops. You will have 2 loops on your hook.
- Yarn over and pull through remaining 2 loops on your hook.
Treble Crochet Increase (tc inc)
- Yarn over twice & insert hook in next stitch.
- Yarn over & pull up a loop. You will have 4 loops on the hook.
- Yarn over and pull through 2 loops. You will have 3 loops on your hook.
- Yarn over and pull through 2 loops. You will have 2 loops on your hook.
- Yarn over and pull through remaining 2 loops on your hook
- Repeat steps 1-5 in the same stitch.

Crochet Mermaid Tail Pattern: 0-3 Months
Rnd 1: Magic circle, 12 tc, join with a slip stitch to the first st (12 stitches)
Rnd 2: Ch 3, *tc inc in 3 sts, tc in 3 sts*, join (18 stitches)
Rnd 3: Ch 3, *tc inc in 2 sts, tc in 7 sts*, join (22 stitches)
Rnd 4: Ch 3, *tc inc in 2 sts, tc in 9 sts*, join (26 stitches)
Rnd 5: Ch 3, *tc inc in 2 sts, tc in 11 sts*, join (30 stitches)
Rnd 6: Ch 3, *tc inc in 2 sts, tc in 13 sts*, join (34 stitches)
Rnd 7: Ch 3, *tc inc in 3 sts, tc in 14 sts*, join (40 stitches)
Rnd 8: Ch 3, *tc inc in 3 sts, tc in 17 sts*, join (46 stitches)
Rnd 9: Ch 3, *tc inc in 3 sts, tc in 20 sts*, join (52 stitches)
Waist to Fin Length Instructions
Rnds 10- 20: Ch 3, tc in each st, join (52 stitches)
Rnd 21: Ch 1, sc in each st, join and finish off
Chest to Fin Length Instructions
Rnds 10- 27: Ch 3, tc in each st, join (52 stitches)
Rnd 28: Ch 1, sc in each st, join and finish off
Scroll down for the fin pattern.
Crochet Mermaid Tail Pattern: 3-6 Months
Rnd 1: Magic circle, 12 tc, join with a slip stitch to the first st (12 stitches)
Rnd 2: Ch 3, *tc inc in 3 sts, tc in 3 sts*, join (18 stitches)
Rnd 3: Ch 3, *tc inc in 2 sts, tc in 7 sts*, join (22 stitches)
Rnd 4: Ch 3, *tc inc in 2 sts, tc in 9 sts*, join (26 stitches)
Rnd 5: Ch 3, *tc inc in 2 sts, tc in 11 sts*, join (30 stitches)
Rnd 6: Ch 3, *tc inc in 2 sts, tc in 13 sts*, join (34 stitches)
Rnd 7: Ch 3, *tc inc in 3 sts, tc in 14 sts*, join (40 stitches)
Rnd 8: Ch 3, *tc inc in 3 sts, tc in 17 sts*, join (46 stitches)
Rnd 9: Ch 3, *tc inc in 3 sts, tc in 20 sts*, join (52 stitches)
Rnd 10: Ch 3, *tc inc in 3 sts, tc in 23 sts*, join (58 stitches)
Waist to Fin Length Instructions
Rnds 11- 23: Ch 3, tc in each st, join (58 stitches)
Rnd 24: Ch 1, sc in each st, join and finish off
Chest to Fin Length Instructions
Rnds 11- 33: Ch 3, tc in each st, join (58 stitches)
Rnd 34: Ch 1, sc in each st, join and finish off
Scroll down for the fin pattern.
Fin Pattern for Both Sizes
Lay your mermaid tail flat and make sure that your stitches with the increases are in the middle (see figure 1)

Attach your yarn on the side of the tail in the space between rows 5 & 6 (see figure 2)

Working away from tail: –>
Working back towards tail: <–
Make your first sc in the space between rows 5 & 6. Continue to sc around the tc sts on each round and in the space between each round- you will sc down one side, sl st in the middle at the bottom, and continue to sc up the other side until you reach the area between rows 5 & 6, do NOT finish off, begin pattern below (see figure 3)

Row 1: (see figure 4) Ch 36, dc in 2nd ch from hook and in each rem ch, sl st in 2nd sc on tail (35 stitches)

Row 2: –> Ch 2, working in back loops dc 34 (34 stitches)
Row 3: <– sl st in first st, ch 2, working in front loops dc 33, sl st in 3rd sc on tail (33 stitches)
Row 4: –>Ch 2, working in back loops dc 32 (32 stitches)
Row 5: <–sl st in first st, ch 2, working in front loops dc 31, sl st in 4th sc on tail (31 stitches)
Row 6: –> Ch 2, working in back loops dc 30 (30 stitches)
Row 7: <– sl st in first st, ch 2, working in front loops dc 29, sl st in 5th sc on tail (29 stitches)
Row 8: –>Ch 2, working in back loops dc 28 (28 stitches)
Row 9: <– sl st in first st, ch 2, working in front loops dc 27, sl st in 6th sc on tail (27 stitches)
Row 10: –> Ch 2, working in back loops dc 26 (26 stitches)
Row 11: <– sl st in first st, ch 2, working in front loops dc 25, sl st in 7th sc on tail (25 stitches)
Row 12: –> Ch 2, working in back loops dc 24 (24 stitches)
Row 13: <– sl st in first st, ch 2, working in front loops dc 23, sl st in 8th sc on tail (23 stitches)
Row 14: –> Ch 2, working in back loops dc 22 (22 stitches)
Row 15: <– sl st in first st, ch 2, working in front loops dc 21, sl st in 9th sc on tail (21 stitches)
Row 16: –> Ch 2, working in back loops dc 20 (20 stitches)
Row 17: <– sl st in first st, ch 2, working in front loops dc 19, sl st in 10th sc on tail (19 stitches)
Row 18: –> Ch 2, working in back loops dc 18 (18 stitches)
Row 19: <– sl st in first st, ch 2, working in front loops dc 27, sl st in 11th sc on tail (17 stitches)
Row 20: –> Ch 2, working in back loops dc 16, 2 dc in last st (18 stitches)
Row 21: <– working in front loops, ch 2, 2 dc in 1st st, dc 17, sl st in 12th sc on tail (19 stitches)
Row 22: –> Ch 2, working in back loops, dc 18, 2 dc in last st (20 stitches)
Row 23: <– working in front loops, ch 2, 2 dc in 1st st, dc 19, sl st in 13th sc on tail (21 stitches)
Row 24: –> Ch 2, working in back loops, dc 20, 2 dc in last st (22 stitches)
Row 25: <– working in front loops, ch 2, 2 dc in 1st st, dc 21, sl st in 14th sc on tail (23 stitches)
Row 26: –> Ch 2, working in back loops, dc 22, 2 dc in last st (24 stitches)
Row 27: <– working in front loops, ch 2, 2 dc in 1st st, dc 23, sl st in 15th sc on tail (25 stitches)
Row 28: –> Ch 2, working in back loops, dc 24, 2 dc in last st (26 stitches)
Row 29: <– working in front loops, ch 2, 2 dc in 1st st, dc 25, sl st in 16th sc on tail (27 stitches)
Row 30: –> Ch 2, working in back loops, dc 26, 2 dc in last st (28 stitches)
Row 31: <– working in front loops, ch 2, 2 dc in 1st st, dc 27, sl st in 17th sc on tail (29 stitches)
Row 32: –> Ch 2, working in back loops, dc 28, 2 dc in last st (30 stitches)
Row 33: <– working in front loops, ch 2, 2 dc in 1st st, dc 29, sl st in 18th sc on tail (31 stitches)
Row 34: –> Ch 2, working in back loops, dc 30, 2 dc in last st (32 stitches)
Row 35: <– working in front loops, ch 2, 2 dc in 1st st, dc 31, sl st in 19th sc on tail (33 stitches)
Row 36: –> Ch 2, working in back loops, dc 32, 2 dc in last st (34 stitches)
Row 37: <– working in front loops, ch 2, 2 dc in 1st st, dc 33, sl st in 20th sc on tail (35 stitches)