What should Muslim women wear to the gym?

The basic rule

Outside the home, in front of men who aren't her mahram, a Muslim woman covers her body except the face and hands (some scholars, mainly Hanafi, also allow the feet). Clothing should be loose and thick enough not to show the body's shape or skin. The Quran says:

The Prophet ﷺ warned about "women who are clothed yet naked" (Sahih Muslim 2128), which scholars explain as clothes that are tight or thin enough to show what they're meant to cover. See Can I wear tight or see-through clothes with hijab?

A practical mixed-gym outfit

• Top: a long, loose, breathable sports tunic or oversized T-shirt that falls to mid-thigh or lower, with a long-sleeved base layer if the sleeves are short.
• Bottoms: joggers, wide-leg track pants, or leggings worn under a long top. Leggings on their own are too revealing for most scholars.
• Head: a slip-on sports hijab or a cotton underscarf with a short, pinned wrap. See How do I wear hijab for sports?
• Fabric: moisture-wicking, matte and dark or mid-tones; sweat makes thin light fabrics see-through.

In a women-only gym

Among women, the awrah is much smaller: most scholars say from the navel to the knee, though many advise wearing more than the minimum in shared spaces. You can usually train in a T-shirt and leggings with no hijab, as long as no men can see in and no one is filming. See Can I take off my hijab at a women-only gym?

Brands and budget

Several modest sportswear brands now sell full outfits, and mainstream brands sell sports hijabs and long tunics. You don't need to buy anything special: a long running shirt, a sports hijab and joggers you already own will do the job.