Bandeau

A bandeau is a strip of fabric around the chest. Most modern versions are a tube of stretch knit, lace or swim fabric, sometimes with a ruched or twisted center and sometimes with thin removable pads, held up by its own tension and an elastic edge. There are no wires, no shaped cups and usually no straps or fastening; it pulls on over the head or steps in.

Support is minimal. The bandeau suits small busts, layering under sheer or loose tops, lounging, and swimwear, where the same shape is one of the standard bikini tops. Larger busts tend to find that it slides down and flattens rather than holds.

The word is French for a band, and in lingerie history it belongs to the 1920s. The flapper silhouette called for a flat, boyish chest, and bandeau brassieres with thin straps and no cups were made to flatten, not lift, some with light boning early in the decade and simpler elastic versions later. Even then the market was shifting: research by the J. Walter Thompson agency in 1924 and 1925 found younger buyers already asking for uplift styles.

A strapless bra looks similar from a distance but has molded cups, wire and a hook closure. A sports bra has straps and a deep band. A bralette has straps and some cup shaping, however soft.

A bandeau stays up by grip and tension and nothing else. Every fit question comes back to that: the band has to be tight enough not to slide, and loose enough not to flatten you into one shelf.

Busts that suit it, and the point where it stops working

The bandeau is at its best on small and medium busts, roughly A to C cups. It also works as a layer under clothes that do the supporting themselves, such as a corset top or a lined bodice. Wear it for lounging, travel days and warm weather, when a wired strapless bra feels like too much.

Above a C or D cup, most people find that a plain tube slides down within the hour and squashes the bust rather than holding it. If that is you, look for a version with boning or straps, or go to a strapless bra with wire and molded cups. Narrow, sloping ribcages also tend to lose a bandeau faster, because there is less shape for the band to grip.

Grip strips, side boning and shirring

Look at the inside edges before you buy. The details that hold a bandeau in place are small, and they vary a lot between brands.

Silicone grippers

A line of silicone along the top and bottom edges is the most useful single feature. Cosabella's Free Cut Micro Bandeau has grips along both edges, plus side boning, in a microfiber of 80 percent polyamide and 20 percent elastane.

Shirring and two-layer fronts

A gathered or shirred center pulls the fabric in between the breasts and gives a little separation. Commando's Double Take Lace Bandeau uses bust shirring with a microfiber front and four-way stretch lace across the back.

Pads and optional straps

Removable pads add shape and nipple coverage. Some bandeaus also come with straps. ThirdLove's Seamless Stretch Cotton Wireless Bandeau has a light spacer-foam lining and multi-way straps, which turn it into something closer to a bralette on days when you need more hold.

What to wear it under

Off-the-shoulder and one-shoulder tops are the obvious match, along with tube dresses and halter necks. A bandeau is also the tidy option under sheer shirts and wide armholes, where a bra with straps and hooks would look busy. Under an open-back top, check that the band sits below the lowest point of the opening.

Pick a color close to your skin tone for sheer layers, or a contrasting one if the bandeau is meant to show. Thin T-shirts are less forgiving. A single-layer bandeau shows nipples through jersey, and a ruched one can print through as a ridge.

Sizing a bandeau sold in S, M and L

Most bandeaus come in letter sizes, so the brand's chart matters more than your usual bra size. Cosabella's runs from P to L, Commando's from XS/S to L/XL, and Girlfriend Collective sells its double-lined bandeau from XXS to 6XL. Measure your underbust and full bust, then compare both with the chart. If you fall between sizes, the smaller one usually stays up better, as long as it does not leave a red line.

Two quick tests tell you whether it fits. Raise both arms above your head: the band should stay where it was. Then sit down and lean forward. If the top edge rolls over or the band creeps down, the size is wrong or the style lacks grip.

Keeping the silicone tacky

Silicone grippers lose their tack with heat and body lotion. Wash in cool water, lay the bandeau flat to dry, and keep it out of the dryer. ThirdLove recommends a hand wash in cold water and a garment bag if it goes in a machine. Let any lotion soak in before you put a bandeau on.