Shell Hexagon Cardigan – Free Crochet Tutorial

The Shell Hexagon Cardigan is a bold, flowing garment built from classic hexagon construction and an eye-catching shell stitch pattern. With its dramatic drape, textured shells, and customizable sizing, this cardigan is designed to feel both whimsical and wearable. Whether you prefer oversized sleeves or a more fitted look, this pattern adapts beautifully to your style.

This cardigan is worked from two large hexagons, then extended, shaped, and joined to create sleeves, body, and neckline. The construction is intuitive once the base hexagon is complete, making it a fun and rewarding project for adventurous crocheters.

What makes the Mermaid Shell Hexagon Cardigan truly special is its versatility. The hexagon construction allows you to customize the fit at every stage, from sleeve width to overall length, making it easy to adapt the design to different body types and style preferences. The repeating shell stitches create beautiful movement and texture, especially when worked with gradient or mermaid-inspired yarns, turning this cardigan into a standout handmade garment.

Shell Hexagon Cardigan

Skill Level

Intermediate

(Confident beginners may also enjoy this pattern if comfortable with shells and garment construction.)

Materials

• DK weight yarn

  • Main color (shells / “mermaid” color)

Yarn Notes:
Smooth or lightly variegated yarns show the shell texture best. Color-changing yarns work beautifully for a mermaid effect.

Gauge

Gauge is not critical for this garment.
Fit is adjusted by adding or removing rounds.

Finished Size

Customizable

• Adjust size by increasing hexagon rounds

• Sleeves and body length are added after assembly

Stitch Abbreviations (US Terms)

• ch – chain

• sl st – slip stitch

• sc – single crochet

• dc – double crochet

• hdc – half double crochet

Pattern Notes

• Cardigan is constructed from two hexagons

• Each hexagon has 6 corners

• Corners are always worked into the same corner spaces

• Shells are worked with 7 double crochets

• Single crochets anchor shells and control spacing

• Stitch markers are highly recommended to identify corners

HEXAGON MOTIF

Round 1 – Center

1. Ch 5, join with sl st to form a ring
   (Magic ring may be used if preferred)

2. Work a stacked dc or ch 3 (counts as dc)

3. Ch 2

4. Dc into ring

5. Ch 2

Repeat dc, ch 2 until you have 12 dc total, each separated by ch 2.

6. Join with sl st to top of starting dc.

Round 2 – Shell Setup

Switch to shell color (if using two colors).

1. Attach yarn in any ch-2 space

2. Ch 1, sc in same space

Shell Pattern:

• In next ch-2 space: 7 dc

• Next ch-2 space: sc

Repeat around.

You will have 6 shells total.

Join with sl st to first sc.

Round 3 – Corner Formation

Switch to contrast color.

In each sc between shells, work a corner:

• dc

• ch 2

• dc

• ch 2

• dc

• ch 2

• dc

(4 dc with ch-2 spaces between)

Between corners, ch 4 or ch 5 (keep consistent).

Join with sl st.

You now have 6 clear corners.

Round 4 – Shell Expansion

Switch back to shell color.

In each corner:

• 7 dc

• sc

• 7 dc

Between corners:

• sc in top of shell

Continue around.

Join with sl st.

Continue Hexagon Rounds

Repeat:

• Contrast color round:

  • Corners into corners

  • V-stitches or dc placements on sides

• Shell color round:

  • Shells in V-spaces

  • sc between shells

Continue until hexagon is large enough:

• Fold in half to check sleeve depth

• Typical adult size: 20–24 rounds (adjust to fit)

Make 2 identical hexagons.

CARDIGAN ASSEMBLY

Fold & Join

• Fold each hexagon into an “L” shape

• Match back panels together

• Join using sl st or join-as-you-go method along back seam

This forms:

• Sleeves

• Front panels

• Back panel

EXTENDING THE BODY

Bottom & Front Extensions

1. Attach contrast color along bottom edge

2. Work V-stitches (dc, ch 2, dc) across

3. Turn and add shell rounds on top

4. Repeat until desired length is reached

SLEEVE EXTENSIONS (Optional)

• Extend sleeves using the same method as body

• To taper sleeves:

  • Skip stitches

  • Use slip stitches to decrease circumference

FINISHING OPTIONS

Scalloped Edge

• Finish with a shell round around entire cardigan

Ribbed Edge (Optional)

1. Work a round of sc evenly

2. Switch to smaller hook

3. Ch 6, sc in back loops only

4. Slip stitch into base every 2 stitches

5. Repeat for cuffs, hem, and neckline

Blocking

Steam blocking is highly recommended:

• Do not stretch aggressively

• Steam relaxes fibers and improves drape

• Always test steam on a swatch first

The Mermaid Shell Hexagon Cardigan is a statement piece that blends classic construction with modern texture. Once you understand the hexagon logic, the pattern becomes intuitive and highly customizable. Play with colors, sleeve length, and borders to make it uniquely yours.