Crochet Mermaid Tail Snuggle Sack in Bernat Pop! - Downloadable PDF

Crochet Mermaid Tail Snuggle Sack in Bernat Pop! – Pattern Summary

This free downloadable crochet pattern from Bernat guides you through creating an enchanting Mermaid Tail Snuggle Sack — a cozy, wearable blanket designed to look like a mermaid's tail. Sized to fit Youth and Adult wearers, this whimsical snuggle sack is crocheted in the round from the bottom up, beginning at the narrow tail tip and expanding outward to a generous body opening. The finished piece measures approximately 23 inches wide by 50 inches long, excluding the decorative tailfin, making it a substantial and satisfying project.

Rated at an intermediate skill level, this pattern is ideal for crocheters who are comfortable working in the round, managing increases, and reading multi-step repeat instructions. It is a rewarding project that combines straightforward technique with a fun, eye-catching result.

What Is Being Made

The finished object is a mermaid tail snuggle sack — a cocoon-style blanket that a person can slip their legs into, mimicking the silhouette of a mermaid's tail. It features a tailfin at the closed bottom end, adding to the realistic mermaid aesthetic. The sack is wide enough at the top for comfortable use by youth and adults alike, and long enough to cover the full body from feet to waist or beyond.

Design Details

• Finished width: Approximately 23 inches (58.5 cm)
• Finished length: Approximately 50 inches (127 cm), excluding the tailfin
• Sizing: Youth/Adult
• Features a separate or integrated decorative tailfin at the base
• Worked entirely in crochet in the round, building from a small foundation outward

Techniques Used

The construction of this snuggle sack relies on a classic bottom-up, worked-in-the-round approach. The sack begins with a very small foundation — a chain of 4 — and the first round is worked into the fourth chain from the hook to create a tight circular base. From there, the pattern expands through carefully placed increase rounds interspersed with even rounds to shape the tapered tail silhouette.

Key Construction Techniques

• Working in the round: Every round is joined with a slip stitch to the top of the beginning chain-3, which counts as the first double crochet throughout the pattern
• Gradual shaping with increases: Increase rounds are strategically placed — for example, doubling stitches in the early rounds and then spacing increases further apart as the sack widens — to create the characteristic flared mermaid tail shape
• Even rounds: Plain double crochet rounds are worked between increase rounds to maintain fabric structure and prevent overly rapid flaring
• Stitch counting: The pattern tracks stitch counts carefully at each increase round (e.g., 8 dc, 16 dc, 24 dc, 32 dc, 40 dc, 48 dc, and continuing upward), which is essential for maintaining correct shaping
• Tailfin construction: A separate tailfin section is included to complete the mermaid aesthetic at the base of the sack

Stitches Used

The pattern is built almost entirely on a foundation of double crochet (dc), making it accessible to intermediate crocheters who are already comfortable with this fundamental stitch. The repetitive nature of the double crochet fabric also means the project works up relatively quickly despite its large size.

Stitch Breakdown

• Chain (ch): Used for the foundation and at the beginning of each round (ch 3 counts as dc)
• Double crochet (dc): The primary stitch used throughout the entire sack body
• Increase (2 dc in one stitch): Used in increase rounds to expand the stitch count and shape the sack
• Slip stitch (sl st)