Here are well-known five‑star hotels in Mumbai that offer luxury spa and wellness centres (hotel → spa name + short highlight). I’ve linked each item to the hotel’s official spa/wellness page for details and bookings.

• Taj Mahal Palace, Colaba — J Wellness Circle / Jiva Spa (holistic Ayurvedic rituals, hammam, floatation/Dead Sea soak and signature treatments). (tajhotels.com)
• The Oberoi, Mumbai (Nariman Point) — The Oberoi Spa (signature Oberoi, Eastern & Western therapies; complimentary morning yoga; full spa menu). (oberoihotels.com)
• Four Seasons Hotel Mumbai — Four Seasons Spa & wellness (Ayurveda, signature rituals, yoga and personalized programs). (fourseasons.com)
• JW Marriott Mumbai Juhu — The Spa / Quan-style luxury treatments (massages, marine wraps, beauty therapies, pools & fitness). (marriott.com)
• The St. Regis Mumbai (Lower Parel) — St. Regis Spa (luxury treatment menu, pool & fitness offerings). (marriott.com)
• Sofitel Mumbai BKC — Sofitel Spa with L’Occitane (French spa brand treatments, couples suite, Jacuzzi). (sofitel-mumbai-bkc.com)
• ITC Maratha, a Luxury Collection Hotel — Kaya Kalp – the Spa (Ayurveda, indigenous rituals, infinity pool & gym). (itchotels.com)
• The Leela Mumbai — The Leela Spa (holistic body scrubs, massages, Ayurvedic options and fitness/yoga programs). (theleela.com)
• Grand Hyatt Mumbai — Club Oasis / hotel wellness centre (multi‑treatment spa, sauna/steam, fitness & yoga). (expedia.com)
• Trident Hotels (e.g., Trident Nariman Point / Trident BKC) — Trident Spa (signature dhara, Balinese, Ayurvedic and other therapies; resident-guest access policies). (tridenthotels.com)

Quick notes

• Spa access, hours, membership or external bookings vary by hotel (some spas prioritise in‑house guests or require membership/reservation). For example, The Oberoi notes the spa is prioritised for resident guests; confirm policies and book in advance. (oberoihotels.com)
• For pricing, current availability, treatment menus or to book appointments, use the hotel’s spa page or contact the hotel directly (links above).

If you want, I can: (a) narrow this to a specific neighbourhood (Colaba, Juhu, BKC, Lower Parel), (b) compare two or three