Men need 2+ sets of white احرام cloth plus casual clothes; women need modest clothing in breathable fabrics; both need comfortable broken-in walking sandals and sun protection.
Men need at least 2 sets of احرام garments — each set consists of two pieces of white, unsewn cloth: the izar (lower garment wrapped around the waist) and the rida (upper garment draped over the shoulders). Purchase quality احرام cloth with some thickness to avoid transparency. Practice wrapping them securely before your trip. For non-احرام days, pack lightweight, loose-fitting clothing in breathable fabrics like cotton — avoid synthetic materials in the extreme heat.
Women do not have a specific احرام garment — any modest clothing that covers the body (except face and hands) serves as احرام. Pack loose, comfortable abayas or similar modest garments in light colors to reflect heat. Bring a variety of hijabs in breathable fabrics. Avoid dark colors that absorb heat.
For both genders, pack: comfortable broken-in walking sandals (men must wear footwear that exposes the ankle bone during احرام), a good pair of walking shoes for non-احرام times, a sun hat or umbrella for shade (men cannot cover their head during احرام), light sleepwear, an extra set of undergarments, and a money belt or small pouch. Consider bringing an احرام belt with pockets since احرام garments have no pockets. Keep luggage light — you will be moving between locations frequently.