Crochet sea urchin pattern — one piece, 12 rounds, knotted spines
This free crochet sea urchin pattern makes a deep purple ball about 3.5 cm across, about 6 cm across once the spines are on, worked on a 3 mm hook in four colours in under an hour. Twelve rounds is the whole of the crochet — a plain sphere out to 24 stitches, five straight rounds, then back in, with the last two rounds swapped to black for the mouth underneath — and the spines go on afterwards, knotted through roughly every third stitch over rounds 3 to 10 and trimmed at the end. All 12 rounds are written out below with the stitch count each one ends on.
Maths verified, not yet made. Every one of the 12 rounds was checked against the round before it by machine — the counts, the increases and the decreases all add up. What nobody can promise you yet is how it sits in the hand.How we check
6 of 8 checks ran on 2026-09-04
- 1 format and stitch chainscripts/validate.py — 113 patterns, all counts chain.
- 2 catalogue auditscripts/audit-patterns.py — 113 audited, 0 errors, 66 warnings.
- 3 geometrygeometry-check.py — 113 checked, 0 errors, 4 warnings.
- 5 not a duplicate113 distinct display names across 113 patterns
- 6c target on the recordseo.headKeyword, confidence and demand present and cross-checked by scripts/validate.py
- 8 page readinessscripts/check-completeness.py --gate — 0 required fields missing, 114 editorial flags, 0 unearned claims.
Not yet checked
- 4 render matches the pattern — no image has been compared against its own prompt, so a render showing a piece the rounds do not make would not be caught here. Nothing has counted how many do.
- 6a recognisability — provenance.recognisability is empty in every pattern, so there is no feature list to check the parts against.
Why it is rated Easy
Easy: twelve rounds of plain sphere shaping and one colour change. The knotting takes longer than the crochet does, and none of it needs counting.
Sell what you make. Anything you crochet from this pattern is yours to sell — any quantity, no fee, no credit required.
00
00What you need before you start
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What you need before you start
Yarn — four colours, all weight 3
1 small skein (about 15 g)DK cotton
scrapsDK cotton
scraps, about 3 mDK cotton, cut into lengths and knotted on
scraps, about 1 mDK cotton, cut into lengths and knotted on
Tools
4 you probably own, 1 to buyYou likely have
Tapestry needle
Scissors
Stitch markers
A ruler or a 4 cm strip of card to cut the spines against
You need to buy
Polyester stuffing (~8 g)
Optional
A stitch marker in a contrast colour for the round start
Small sharp scissors for trimming the spines evenly
Gauge and finished size
the last check before you cast onTension
Work tight enough that the stuffing cannot show between stitches. Exact gauge does not matter — a looser hand gives a slightly larger urchin.
Finished size
~3.5 cm across the body, ~6 cm across with the spines
How to make the sea urchin
Switching rewrites every round:US6 sc in mrUK6 dc in mrWork a US sc as a UK single crochet and the fabric comes out looser and taller.
1
01The body
A plain sphere: out to 24 stitches, five rounds straight, then back…12 RNDS
starts in deepPurple· magic ring· Piece 1 of 1
First six rounds[6] [12] [18] [24] [24] [24]
Opening out
RND 1–41[6]
2[12]
3[18]
4[24]
Straight sides
RND 5–95[24]
6[24]
7[24]
8[24]
9[24]
Closing in, black from round 11
RND 10–1210[18]
11[12]
12[6]
US termsmrmagic ringscsingle crochetincincreasedecdecreasest(s)stitch, or stitches
When this piece is doneStuff it firmly before the black rounds close it — the shape should feel solid rather than soft. Then knot the spines on over rounds 3 to 10 and trim them to about 1.5 cm.
You are here
Seven notes on the sea urchin
Read themClose
01An original Crochet Genie design.
02Worked in a continuous spiral. Nothing is joined and nothing is turned, so mark the first stitch of every round and move the marker up as you go.
03The spines are not crocheted. Cut 8 cm lengths of magenta, fold each in half, pull the fold through a stitch with the hook and draw the two ends through the loop — the same knot as a fringe. Work over rounds 3 to 10, roughly every third stitch, and drop in a coral pink one every fifth or sixth knot so the colour is scattered rather than banded.
04Knot the spines on after the body is finished and closed. Doing it while the piece is still open is easier to reach but leaves you crocheting around a fistful of loose ends.
05Trim the spines to about 1.5 cm once they are all on. Trimming at the end is what makes them read as one even coat rather than a set of separate tufts.
06Change to black at the start of round 11 and carry on to the close — those last two rounds sit underneath as the mouth. Secure both ends inside before the opening gets too small.
07Stuff firmly at the end of round 10, before the black rounds close the shape in. A sea urchin's shell is rigid, so this one wants more stuffing than it looks like it needs.
Four questions this pattern answers
Not questions anybody asked. Each one is written from this pattern's own record, and every answer is read off the fields it names.
Is there a gauge to match for the sea urchin?
How much yarn will the sea urchin take?
What hook will the sea urchin need, and what is the finished size?
How long will the sea urchin take to crochet?
A round that will not add up?
Tell us the piece and the round number — the stepper already knows where you are.There is nowhere to send one yet.
Put the laptop down mid-round
The iPhone app keeps your place — piece of 1, round of — and hands it back where you left it.
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