Band Side Bikini Bottom

More Styles Than You Can Make In Your Life Time

The simple and relatively conservative band-side bottom is still the most popular and definitely the easiest to make. You can cut the waist as high as you like, add a fold over section to the top, add a belt stand and loops or even cut away a part of the side band to put in rings or other accessories without even a challenge.


The pattern I'm going to illustrate here is the current hipster style but you can use the same instructions to make even fuller briefs once you have a handle on the technique. Below is a slide show of so many different back widths and styles, including a thong and the newer T-bar thong style. I'll show you how to adapt this quite basic pattern to all of these styles.

Photos found on the Internet (I do not own copyright);
used for the purpose of illustration/education only.

We're going to start by creating a basic band side bottom with wide back, and add the lines for narrower styles (see Illustration below). This pattern is based on the Women’s One Piece Block we created previously (using 12% horizontal negative ease and 0% vertical ease). Before you start each step, take a good look at the illustration to help you follow the drafting process. At the end of each step your draft should match the illustration.

Step One

Trace out the bottom halves of your one piece blocks on to a new sheet (it's easier to do this on a folded piece of tracing paper so you can work from both sides and overlay them over again if needed. Draft in a top line (shown in red). This line can be at any position but must be square to the centre front/back and square to the side seam ... 2-3cm lower at the center is ok, but don't square straight across. Current styling is the hipster look which would be between 3 and 5cm above the leg hole ... I've used 4cm.

Step Two

Separate the front and back panels. You could literally stop here, add your seam allowance and labelling and you're done. It's that easy. However this is not good enough for retail and too messy for commercial production. The following steps demonstrate how to improve the pattern for commercial production.

Step Three

Overlay the panels again. Draft in a guide line perpendicular to the side seam (blue). Choose your desired band width (about 4cm is fine for this example) a draw second line parallel to the first, this width apart.

Draft in a guide line perpendicular to the top of the centre front/back (red line). Where this line intersects the guideline from the top side seam we draft yet another guide line (green) perpendicular to the parallel lines. Ok that was difficult to describe so look at the illustration carefully!

Step Four

Trace the guides through to both front and back panels; remove unnecessary lines until your drafts look like mine. What we are about to do is rotate the rectangles (each the same amount at first) in order to create a smoother pattern.

Step Five

Put a dot in the center of side of the rectangle as shown. Rotate the rectangles about the dots. Rotate each the same amount until the front looks 'better' ... about 10° worked for me. Draw in very smooth and gradual curves to complete the pattern. The one you will find hardest is the back leg line. You must blend smoothly out of the old leg line and then gradually in perpendicular to the side seam. A flexicurve is essential if you're using a pencil and paper. It's easy if you're using CAD.

Step Six

If you're even more of a perfectionist, you can tweak the back panel by rotating the rectangle from the other end about the dot as illustrated. This time your rotating counter clockwise until it looks 'better' again ... about 5° works fine. Redraft the leg line.

You're doing this in two steps for a reason. The first set of rotation brings the side seams to the same position front and back, meaning the garment sits flat on the shelf. The second rotation on the back tweaks the seam into a better position for the back leg line without greatly affecting how the garment sits on the shelf.

Step Seven

Remove unnecessary guidelines. If necessary retrace the front and back panels. Add seam allowance to the pattern based on how you intend to assemble it. I've shown this pattern with 10mm allowance for overlocked seams (8mm to blade plus 2mm off cut) and 10mm allowance for folding over 9mm elastic. If you were to use a binder attachment to apply the elastic and casing fabric to the edge, then you wouldn’t need any seam allowance on those particular seams. Finally, be sure to clearly label your pattern pieces with a title, panel name, garment size, cutting instructions, author’s name, date and revision number.

Step Eight

OK you're are finished with the basic style, but let's see how easy it is to vary your designs. There are a couple of important things to remember:

  • You can't undercut the pattern in the shaded area or you will cut the tension lines. 

  • You can't significantly narrow at the crotch line

Other than that you can modify your heart out without worrying about the vertical length. The red leg line is the full width back, the blue line is the medium width back, the green line is the narrow width and the yellow is the very narrow width back. Both the full and medium width backs sit past the center of the cheek so convex outward slightly. Once you narrow more than the center of the cheek you need to keep the back leg line fairly straight/even. The purple line represents the thong back ... note I've removed 2cm at the crotch as the garment shortens as it falls between the cheeks (this might apply to some of the narrower backs too so be careful how far you go). Lastly the red line at the center back represents the extra height of the T bar thong ... that's actually all there is to it ... that little bit extra holds it squarer than a normal thong and gives the illusion of a taller back bar by apparently lowering the leg line a little ... doesn't take much!

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