The best bra solutions for halter tops are a convertible bra, a strapless bra, or an adhesive bra.
To wear a convertible bra beneath a halter top, you'll need to convert it to a halter style. To do this, unhook the straps from the back, hook them together, and tighten the straps around your neck.
A strapless bra will provide support without straps, which is perfect for a halter top. Look for really sturdy foam cups, silicone gripper, and a wide band. Also, make sure you’re wearing the correct size because anything too big or too small will make it a lot harder for the bra to stay in place.
An adhesive, or sticky, bra is another great option because it provides support without straps or covering your back. These bra cups are made with skin-safe adhesive that sticks directly to your body. This is a great option if you have a C cup or smaller. It can be a bit less effective for larger cup sizes.