Free Crochet Bikini Top Pattern Using Elastic Swim Yarn

This elastic crochet bikini top is built for a secure fit that keeps its shape in and out of the water. You crochet two structured triangles in the round, using marked corner stitches to create clean, predictable shaping as the cups grow.

Crochet Bikini Top

Because the sizing is row based, you can easily adjust coverage by stopping earlier for a smaller cup or adding rounds for more depth. A simple eyelet band along the bottom lets you weave in a long back strap for adjustability, and the top point of each triangle creates a strong anchor for neck ties. Once the crochet is complete, you sew each triangle onto bikini cups or a lining, giving the top more support and a smooth finish against the skin.

Materials

Elastic bikini yarn suitable for swimwear
2 mm crochet hook
Stitch markers
Bikini cups or lining fabric
Pointed tapestry needle
Measuring tape
Scissors

Abbreviations and Notes

ch = chain
sl st = slip stitch
sc = single crochet
dc = double crochet
st = stitch
sk = skip
Corner marker rule means the marked stitch is always the middle dc of the five dc corner group
Work tightly and evenly because elastic yarn can stretch and relax during wear
Make two identical triangles before adding straps and assembly

Fit and Sizing Overview

This pattern sizes by rounds rather than fixed stitch counts after the first round
Stop when the triangle is about one finger width larger than your bikini cup for full coverage
If using only lining fabric instead of cups, stop when the triangle matches your preferred coverage on the body
For more coverage add rounds before the eyelet band and edging
For less coverage stop earlier and proceed to the finishing rounds

Gauge Guidance

Gauge is not critical, but consistency is
If the fabric feels too stiff move up one hook size
If the fabric feels too loose or gappy move down one hook size
Elastic yarn usually looks best with firm stitches and minimal holes in the cup area

Triangle Cups Make 2

Cup Foundation Round 1 Magic Ring Circle

Make a magic ring
Ch 3 to count as the first dc
Work 11 dc into the ring for a total of 12 dc including the starting ch 3
Pull the ring closed firmly
Join with a sl st into the top of the starting ch 3

For Cup Shaping Round 2 Turn the Circle Into a Triangle

Begin with a fake dc by working sc then ch 2
Dc in the next 2 sts
In the next st work 5 dc to form Corner 1
Place a marker in the 3rd dc of this 5 dc group
Dc in the next 3 sts
In the next st work 5 dc to form Corner 2
Place a marker in the 3rd dc of this 5 dc group
Dc in the next 3 sts
In the next st work 5 dc to form Corner 3
Place a marker in the 3rd dc of this 5 dc group
Join with a sl st to the top of the fake dc

Cup Growth Rounds 3 and Up Create Depth

Begin the round with ch 3 or a fake dc to match your tension
Dc in each st around
In each marked corner st work 5 dc
Move the marker to the 3rd dc of the new 5 dc group each time you make a corner
Join with a sl st at the end of the round
Repeat these growth rounds until your cup reaches your desired size

How to Know When the Cup Is the Right Size

Place the triangle over your bikini cup or over the bust area
The triangle should be about one finger width larger than the cup edge to allow for sewing and stretching during wear
If the top point feels too sharp add one more growth round
If the sides feel too wide stop and continue to finishing

Cup Count Reference Example

A common size in the tutorial reached the target size after about 10 growth rounds
Your number may be different based on yarn stretch and personal coverage preference

Part 2 Bottom Eyelet Band

Eyelet Round Create Holes for the Back Strap

Start at the bottom edge section of the triangle and work evenly along the lower side
Work dc in the first st
Ch 1
Sk 1 st
Dc in the next st
Repeat dc ch 1 sk 1 across the bottom edge section
Keep the eyelets even so the strap weaves smoothly
When you reach the corner area continue following the edge shape without tightening

Adjusting the Eyelet Spacing

If your stitches are very tight use dc ch 1 sk 0 in some sections to avoid pulling
If your stitches are looser keep dc ch 1 sk 1 consistently

Side Edge Decorative Finish

Side Edging Round Create a Clean Decorative Border

Attach yarn at one bottom side corner
Sk 2 sts
In the next st work 3 dc in the same st
Sk 2 sts
Repeat 3 dc in next st sk 2 along the side edge toward the top
Keep the 3 dc groups aligned and avoid adding extra stitches

Top Point Space for Neck Strap

When you reach the very top corner st work 2 dc ch 1 2 dc into the same st
This ch 1 space will be the anchor for the neck strap
Continue down the other side with the same edging pattern

Part 4 Straps

Neck Straps Make 2

Join yarn into the top point ch 1 space
Ch until the strap measures about 50 cm or your preferred length
Dc in the 3rd ch from the hook
Dc in each ch across back to the cup
Sl st into the same top point space to secure
Fasten off neatly
Repeat for the second cup

Neck Strap Fit Notes

For a halter that ties high on the neck make longer straps
For a lower tie behind the neck make slightly shorter straps
Elastic yarn can feel snug so do not undersize the strap length

Back Strap Make 1 Long Strap

Measure around the body under the bust where the band will sit
Multiply that number by 1.5 to add about 50 percent extra length for tying
Example if underbust is 94 cm then strap length target is about 140 cm
Ch until the strap matches your target length
Dc in the 3rd ch from the hook
Dc in each ch across
Fasten off leaving a tail for weaving

Back Strap Options

If you prefer a thinner tie strap do not work back in dc and leave it as chains
If you want a sturdier tie work one row of dc as written
If you want extra firmness work a second row of dc

Assembly and Finishing

Prepare the Cups

Make sure both crochet triangles are the same size
Weave in all ends except those you want to use for sewing
Lightly stretch the triangles and let them relax so you sew them in their natural resting size

Sewing the Crochet to Bikini Cups or Lining

Place one crochet triangle on top of a bikini cup
Align the top point with the cup apex
Thread the pointed tapestry needle with the same elastic yarn
Sew around the outer edge of the cup using small whip stitches
Keep the stitches close together so the edge sits smooth
Do not pull too tightly or the cup edge will pucker
Repeat for the second cup

If You Are Using Lining Fabric Instead of Cups

Cut lining fabric to match the triangle shape with a small seam allowance
Hand stitch the lining to the back of the crochet triangle
Then sew the lined triangle to the strap system as written

Join the Two Cups on the Body With the Strap Weave

Lay both triangles flat with the bottom edges facing inward toward each other
Identify the eyelet band along the bottom of each triangle
Starting at the center area weave the back strap through the eyelets
Weave from center outward so both sides stay even
Continue weaving until the strap exits at the outer bottom edges
Tie the back strap behind the body

Final Fit Check

Put the top on and tie the neck straps first
Adjust the cups so they sit evenly
Tie the back strap securely
If the cups feel too far apart re weave the strap starting closer to the center
If the cups feel too close re weave leaving a slightly wider center gap
If you need more support shorten the back strap slightly or add a second row of dc to thicken it

Finishing

Weave in all remaining ends securely
For swimwear durability weave ends through several stitches and back again
Trim close and avoid bulky knots
If your yarn allows you may carefully melt tips only if the yarn is synthetic and you know it is safe to do so
Rinse and dry flat before first wear to let the elastic settle

Customization Ideas

Add a second edging round in sc for a smoother outline
Add small beads only if they are rustproof and swim safe
Add a center connector such as a small ring and stitch the triangles to it before weaving the back strap
Add removable padding by sewing a small opening in the lining if you use fabric lining