Some time ago I made a medieval bathing dress in unbleached linen, and I wanted to share it with you. It is a simple project, perfect for an evening or if you want to practice hand sewing.
There are plenty of bathing dresses in paintings from the late 14th to 16th century in Europe, they can also be seen in different cuts and models, and some are clearly supportive shifts that you could wear under your medieval clothing. Mine is very simple but with an intake under the bust to allow some support, but still being easy to get in and out from. No lacing is acquired.

Left; Bohemian, Codices vindobonenses 2759-2764 in the Osterreichischen Nationalbibliothek, in Vienna, Austria. Right: The Bathhouse Attendant, Bible of Wenceslaus IV. 1389.

This find is from A History of Costume, Kohler and is dated 14th century and described as a lady’s chemise or undergarment, the photo is old but you get the general idea.

Most of the pictures I have found seems to be dated to the late 14th to early 15th century, there are lots on the internet and I have a Pinterest folder on Medieval underwear so I won’t go into more historical sources today.

The cutting out; prewash your linen, fold in double in the length you would like, and then cut the A shape. I used the leftover fabric for gores in the sides (and at centre front + back if you like, it is optional) but this of course depends on your measures.

The first pictures show the general cut, the second the additional front and pack gores, the third the intake under the bust that give me the support. Do not take in too much, because then you won’t be able to get in and out of the dress.

About measures: The length of the dress measures from armpit to hem. The width is your measure around your bust divided in two (for front and back) add seam allowance but nothing more. Start the gores at your natural waist (if you are unsure, rather place them higher than lower) and pin the intake under your bust while wearing the dress with gores and side seams sewn/basted. Add shoulder straps last, mine is just double-folded linen cloth, whip stitched together and then fastened at the same position as I would have worn bra straps.

If you sew your dress by hand, use waxed linen thread and running stitches, and then fold the seam allowance to one side and whipstitch in place. This gives you a sturdy seam that is also quick to make. Hem the dress with running stitches or whip stitches, after your choice.

Making the dress in unbleached linen made it opaque even when it was wet, good for modesty. In artwork the dress seems to be white, may be visible nipples was a thing, or you would have to pick a very dense fabric. In some pictures, it is very clear that the fabric is transparent, but I chose the more sturdy and practical look. (update spring 2021: I have found that if you start with unbleached linen fabric, and sun bleach it yourself you will get an almost white fabric that is not as transparent as the modern bleached options in stores.)

The result? All considered, I am satisfied with the cut, sewing and look of the dress. It is also easy to swim in. Historically, being out in public in a bathing dress was not a thing, they can be seen on bathhouse attendants or in rare cases during the dressing/undressing at home or during dirty labour. Wearing it to the beach was certainly not a thing, but I liked to have a more historical dress instead of wearing a modern bikini when going for a swim at events.