Siren Bikini in Adriafil Tender - Downloadable PDF

Siren Bikini Crochet Pattern in Adriafil Tender Yarn — Free Downloadable PDF

The Siren Bikini is a charming, beach-ready two-piece crochet pattern that produces a complete matching set consisting of bikini panties and a bra. Designed for a size 40, this pattern is offered as a free downloadable PDF and is worked entirely in crochet using Adriafil Tender yarn. The finished piece has a playful, handcrafted aesthetic enhanced by decorative plastic beads and a neat costume lining for a polished, wearable result.

What Is Being Made

This pattern creates a full crochet bikini set made up of two separate components:

• Bikini panties — worked in two pieces (front and back) with carefully shaped sides to create a flattering, fitted silhouette through a series of increases and decreases.
• Bra cups — each cup is constructed individually, beginning with a small foundation chain and built up with rows of double crochet to form a shaped, structured cup.

The combination of shaping techniques and decorative finishing details makes this a rewarding intermediate crochet project suitable for those comfortable with basic crochet shaping.

Techniques Used

The Siren Bikini relies on fundamental but effective crochet construction techniques throughout both the panties and the bra:

• Side shaping through decreasing — the bikini front is shaped by decreasing 1 stitch on each side every 2 rows three times, then every 4 rows four times, creating a gentle curve inward toward the gusset area.
• Side shaping through increasing — after the narrowest point, stitches are increased 1 stitch every 4 rows five times, then 1 stitch every 2 rows seven times, flaring the piece back out to full hip width.
• Working on both sides of a foundation chain — the bra cups are constructed by working double crochets along the initial chain and then continuing on the opposite side of that same chain, a technique that allows the cup to grow outward from a central starting point.
• Turning with chain stitches — standard turning chains are used throughout to maintain even edges at the start of each new row.
• Bead embellishment — 22 plastic coloured beads of 0.5 cm diameter are incorporated as decorative details, adding a distinctive, summery character to the finished bikini.
• Lining attachment — a 25 x 18 cm salmon-coloured costume lining is used to finish the bikini panties, providing opacity, comfort, and a professional finish typical of handmade swimwear.
• Elastic thread integration — yellow elastic knitting thread is used to ensure the garment retains its shape and fits securely when worn.

Stitches Used

The pattern is intentionally accessible, using only two core crochet stitches throughout the entire bikini set:

• Chain stitch (ch) — used to create the foundation chains for both the panties and the bra cups, as well as for turning at the beginning of each row.
• Double crochet (dc) — the primary stitch used for all fabric sections of both the panties and the bra. In UK crochet terminology, double crochet produces a tight, dense, and sturdy fabric well suited to swimwear construction.

The simplicity of the stitch selection means that the texture and structure of the finished fabric come primarily from the yarn itself and the shaping rows, rather than from complex stitch patterns. This makes the pattern approachable for crocheters who are still building their skills beyond the beginner stage.

Tension and Sizing

Achieving the correct tension is particularly important for a fitted garment like a bikini. The pattern specifies a tension of 14 stitches and 18 rows to 10 x 10 cm, worked in double crochet using a 4.50 mm crochet hook. This tension is worked with Adriafil Tender yarn and should be checked carefully before