Free Crochet Bikini Pattern with Adjustable Straps

There is something undeniably satisfying about wearing a swimsuit you made with your own hands. Crochet swimwear has had a massive resurgence in recent years, and for good reason — it allows you to control the fit, the color, the style, and the overall vibe in a way that off-the-rack pieces simply cannot match. Whether you are a seasoned crocheter looking for a fun summer project or an intermediate maker ready to take on something wearable, this free crochet bikini pattern with adjustable straps is exactly what you need to add to your project queue.

This pattern is designed to be beginner-friendly in its approach while still producing a polished, stylish result. The adjustable straps are the real star of the show here — they make the bikini genuinely wearable for a wide range of body types without requiring you to measure and recount every row from scratch. Once you understand the basic structure, you can easily resize and modify the pattern to suit your preferences.

Let’s dive in.

What You Will Need

Before you cast on a single stitch, gather your materials. Having everything laid out before you start saves time and keeps the creative momentum flowing.

Yarn: Choose a yarn specifically designed for swimwear or one that handles moisture well. Cotton yarn is the most popular choice for crochet bikinis because it is breathable, relatively quick-drying, and feels soft against the skin. Nylon-blend yarns or those marketed as “beach yarn” are also excellent choices since they resist stretching when wet and dry faster than pure cotton. Avoid acrylic yarn for swimwear — it does not handle water well and can feel uncomfortable when damp.

Recommended weight: Size 2 (fine) or Size 3 (light) yarn works beautifully for swimwear. Finer yarn creates a more drape-y, elegant fabric, while a slightly heavier weight gives you more coverage and structure.

You will need approximately 200–300 yards for the top and 150–200 yards for the bottom, depending on your size and any modifications you make.

Hook: A 2.5mm to 3.5mm crochet hook works well for this weight of yarn. Always check your gauge before starting the pattern, as hook size can vary between makers.

Notions:

• Stitch markers (at least 6)
• Yarn needle for weaving in ends
• Scissors
• A measuring tape
• Optional: thin elastic cord for the waistband of the bottoms

Gauge: 16 stitches and 20 rows = 4 inches in single crochet using your chosen hook and yarn. Gauge really matters in wearable projects, so take the time to make a swatch and measure carefully.

Abbreviations Used in This Pattern

This pattern uses standard US crochet terminology.

• ch — chain
• sc — single crochet
• hdc — half double crochet
• dc — double crochet
• sl st — slip stitch
• sp — space
• st — stitch
• rep — repeat
• tog — together
• BLO — back loop only
• RS — right side
• WS — wrong side
• rnd — round
• sk — skip

Understanding the Adjustable Strap System

The adjustable strap design in this pattern is what sets it apart from most free crochet bikini patterns you will find online. Rather than crocheting straps to a fixed length and hoping they line up perfectly with your body, this pattern creates long strap extensions with a simple tie mechanism that allows you to customize the length, the neckline depth, and the back closure every single time you put it on.

The straps are worked as long chains with a crochet border, creating a flat, ribbon-like appearance that ties easily and lies flat against the skin. You can tie them as a halter, behind the neck, behind the back, or in a bow at the front — the choice is yours, and you can change the styling every time you wear it.

Part One: The Bikini Top

Step 1: Make the Triangle Cups

This top uses two separate triangle pieces that are joined in the center. Each triangle is worked from the bottom point upward, increasing on each row to create the cup shape.

Foundation: Make a magic ring.

Row 1 (RS): Ch 2 (counts as first hdc), 2 hdc into the ring. Turn. (3 sts)

Row 2: Ch 2, hdc into first st, 2 hdc into next st, hdc into last st. Turn. (5 sts)

Row 3: Ch 2, hdc across, working 2 hdc into the center stitch. Turn. (7 sts)

Row 4: Ch 2, hdc into each st, working 2 hdc into center stitch. Turn. (9 sts)

Continue this increase pattern — adding 2 stitches per row by working 2 hdc into the center stitch — until your triangle measures approximately 5–7 inches across the top edge, depending on your cup size preference. For a fuller cup, work more rows. For a smaller, more minimalist look, stop a couple of rows earlier.

Make two identical triangles and set them aside.

Step 2: Join the Triangles

Place both triangles with their right sides facing you, long top edges up.

Hold them side by side so the inner edges are touching. Using your yarn and hook, sl st through both inner edges to join them together with a seam of approximately 1–1.5 inches. This creates a gentle center front that lies flat against the chest.

Alternatively, you can leave the centers unjoined for a slightly separated look that works better for fuller busts.

Step 3: Work the Band

The band runs along the bottom of both cups and extends outward on each side to create the ties.

With RS facing, join yarn at the outer bottom corner of one triangle.

Row 1: Ch 1, sc evenly across the bottom edge of both triangles. Turn.

Row 2: Ch 1, sc in BLO across. Turn.

Row 3: Ch 1, sc in each st across. Turn.

Repeat Rows 2–3 twice more for a band that is about 6 rows deep.

Do not fasten off. Instead, continue working the tie on each side.

Step 4: Make the Side Ties

Without cutting the yarn, continue working a strap from each outer edge of the band.

Ch 80–100 (this creates roughly 18–22 inches of tie length). Work sc back down the chain, beginning in the second ch from hook. Sl st into the edge of the band to secure. Fasten off and weave in ends.

Repeat on the opposite side.

These ties wrap around your torso and tie at the back, holding the band in place.

Step 5: Work the Shoulder Straps

With RS facing, join yarn at the top outer corner of one triangle.

Ch 90–110 (approximately 20–25 inches, or more if you prefer extra length for tying flexibility).

Work sc back down the chain beginning in the second ch from hook. Sl st into the top corner to secure. Fasten off.

Repeat on the opposite side.

These straps go over the shoulders and can be tied at the nape of the neck as a halter, crossed behind the back and wrapped around the band, or looped through each other for different styling options.

Step 6: Add an Optional Decorative Edge

For a polished finish, work a simple picot or shell edging around each triangle cup.

Simple shell edging: Join yarn at any corner, ch 1, then work [sc, skip 1, 5 dc in next st, skip 1] around the outer curved edges of each cup. This gives a scalloped, feminine finish that elevates the look considerably.

Part Two: The Bikini Bottoms

The bottoms are worked in a simple rectangular construction with side ties, making them easy to size and adjust. Unlike some more complex shaped bottoms, this approach gives you a classic bikini silhouette without the complexity of crochet shaping.

Step 1: Make the Front Panel

Foundation chain: Ch 30 (or adjust based on your measurements — this should span your hip measurement divided by roughly 4 to 5, as the sides will stretch to accommodate your full measurement).

Row 1: Sc in second ch from hook and in each ch across. Turn. (29 sc)

Row 2: Ch 1, sc in BLO across. Turn.

Row 3: Ch 1, sc across. Turn.

Repeat Rows 2 and 3 until your panel measures 8–10 inches in length from bottom to top edge, or until it reaches comfortably from your hip to your natural waist when held up.

Fasten off.

Step 2: Make the Back Panel

The back panel is worked identically to the front panel, but typically 1–2 inches wider to provide more coverage. Adjust your starting chain accordingly.

Work the same row pattern as the front panel until the piece measures 10–12 inches in length.

Fasten off.

Step 3: Join Front and Back at the Crotch

Place both panels with right sides together. Using your yarn needle or a sl st seam, join the bottom edges for a seam of approximately 2.5–3.5 inches at the center. This creates the crotch panel.

If you want a more structured crotch area, you can cut a small piece of fabric lining and hand-sew it to the inside of the crotch area. Many crochet swimwear makers find this adds both comfort and confidence when wearing the finished piece.

Step 4: Work the Side Ties

Rather than joining the sides with a seam, these bottoms have open sides finished with long ties that you adjust each time you wear them.

With RS facing, join yarn at the top corner of the front panel’s side edge.

Ch 100–120. Work sc back along the chain beginning in the second ch from hook. Sl st into the corner to secure. Fasten off.

Repeat at the top corner of the back panel on the same side, and then repeat the process on the opposite side for a total of four long ties (two on each side).

To wear, simply align the front and back panels, bring the ties around your hips, and tie them into bows or knots at each side. The length of the ties allows you to adjust how high or low the bikini sits on your hips.

Step 5: Finish the Waistband

Work one row of sc across the top edge of both the front and back panels separately for a clean, even finish. You can also work a round of sl sts through BLO for a subtle ribbed look that helps the top edge hold its shape.

For added support and to prevent the bottoms from shifting during wear, thread thin elastic cord through the top edge or work a row of sc around the top edge over a length of thin elastic. This technique keeps the waistline snug without making the bottoms feel restrictive.

Sizing and Adjustments

One of the most powerful features of this pattern is how easily it adapts. Here are some practical guidance points for adjusting the pattern to different bodies.

For a larger cup size, simply work more rows on each triangle before joining them. You can also increase more aggressively by working increases at both side edges as well as the center point, which creates a rounder, more three-dimensional cup shape.

For a smaller bust, reduce the number of rows and work a tighter gauge. A 2.5mm hook with a fine yarn creates a more fitted, smaller piece.

For the bottoms, the key measurement is your hip circumference. Your front and back panels should each measure roughly half your hip measurement before stretching, as crochet fabric has natural give. If you want less stretch in the fabric, go down a hook size or use a cotton-nylon blend yarn that has less elasticity.

For torso length adjustments, simply add or remove rows on the bottoms panels. The beauty of working flat rectangles is that you have complete control over every dimension.

Caring for Your Crochet Bikini

Handmade swimwear deserves a little extra care to ensure it lasts season after season.

Always rinse your bikini in cold, clean water immediately after swimming, especially if you have been in chlorinated water or the ocean. Both chlorine and salt can break down yarn fibers over time, so a quick rinse goes a long way.

Hand wash your bikini in cool water with a gentle soap or delicate laundry detergent. Avoid scrubbing or wringing the fabric. Instead, gently press the water out and then lay the piece flat on a clean towel, reshaping it as needed before leaving it to air dry. Drying flat prevents the pieces from stretching out under their own weight.

Store your crochet bikini flat or loosely folded rather than compressed at the bottom of a beach bag, which can distort the shape over time.

Styling Your Crochet Bikini

The adjustable strap design opens up a world of styling possibilities beyond the standard halter and side-tie combination.

Try crossing the shoulder straps behind your back and tying them around the band for a sporty bandeau-adjacent look. Loop the side ties of the bottoms slightly higher or lower on your hips to create a different silhouette. Layer the top over a one-piece swimsuit for a boho beach look. Wear the bottoms as shorts over a bikini bottom you already own for added coverage and visual interest.

The top also works beautifully as a festival crop top or a casual summer bralette paired with high-waisted shorts or a flowy skirt. Crochet swimwear has a versatility that extends well beyond the beach, making this project genuinely worth the time you invest in it.

Pattern Notes and Tips for Success

A few final thoughts before you cast on your first stitch.

Always wet-block your finished pieces before wearing them. Submerge the finished bikini in cool water, gently press out the excess moisture, then pin or shape the pieces on a blocking mat and allow them to dry completely. This step evens out your tension, opens up the stitch definition, and gives you a much more professional-looking finished piece.

Work your tie chains with a slightly looser tension than your main fabric. This prevents the ties from being stiff and makes them easier to knot and adjust.

If you are making this bikini as a gift, take the recipient’s measurements and use them to guide your panel sizes rather than following a generic size guide. Crochet swimwear is one of those garments where a small adjustment in dimensions makes a significant difference in how it fits and feels.

Finally, take your time with the join between the two triangle cups. A clean, even join at the center front is one of the details that separates a polished handmade bikini from one that looks obviously homemade. A few extra minutes spent on that seam makes the whole top look more intentional.

Share Your Finished Project

There is a whole community of crochet swimwear makers online who would love to see your finished bikini. If you make this pattern, consider sharing your project on Instagram, Pinterest, or Ravelry with the hashtag #freecrochetbikini or tagging it under crochet swimwear. Seeing how different makers interpret the same pattern — through yarn color choices, strap styling, and sizing adjustments — is one of the most joyful parts of the crochet community.

If you run into any questions about sizing, stitch counts, or modifications, leave a comment below. This pattern is meant to be a living, adaptable starting point, not a rigid set of rules. Crochet is wonderfully forgiving, and swimwear made by hand is always going to be more interesting than anything you could pull off a rack.

Enjoy the process, enjoy the sunshine, and enjoy wearing something you made entirely yourself.