How to Design the Bottoms of a Custom Bikini

Cut the sides of the pair of bikini-cut panties. Get as close as you can to the hem. It does not matter if one side is a little bigger than the other. These panties give you the basic pattern, shape and curves to the inside of the bikini bottoms.

Lay the cut panties on a flat sheet of paper. Wax paper is easy to use and comes in rolls, which makes this step easier. Make an outline of the panties on the wax paper. Draw the outline 1/2 inch from the edge of the panties. This extra fabric is for the hem. For the sides add 1/2 to the sides of the bottom.

Cut the pattern out of the paper. Check the pattern with your body to make sure it is not to small. It is always better to make the pattern too big rather than too small.

Choose the fabric for the bikini. Most swimsuits are made of a Lycra or a Lycra blend, which does well underwater and hugs the body. If the material is light or thin, line the bikini bottom with a second layer of fabric.

Spread the fabric across the a flat surface. Smooth out the fabric to remove any wrinkles. Pin the pattern to the fabric.

Cut around the pattern to create the pattern's shape out of the fabric. Cut out two pieces if the material is light or thin. Remove the pins and pattern from the fabric.

Fold each side 1/4 inch from the edge and sew the hem. If you are lining the bottom, pin the two layers of material together before you sew. If the waistband is elastic, place the elastic before you sew the hem around the waist.

Cut any excess fabric from the sewn hem and try the new bikini bottoms on.