The island has a number of days resort spas. We inlcude the Sheraton spa because it is the closest. The concierge at the clubhouse can also make arrangements for in-room services if you prefer. All reviews below are from Fodor's travel guide.
Mauna Lani Spa. If you're looking for a one-of-a-kind experience, this is your destination. Most treatments take place in outdoor, bamboo-floor hales (houses) surrounded by lava rock. Incredible therapists offer a mix of the old standbys (lomi lomi massage, moisturizing facials) and innovative treatments, many of which are heavily influenced by ancient traditions and incorporate local products. One exfoliating body treatment is self-administered in one of the outdoor saunas -- a great choice for people who aren't too keen on therapists seeing them in their birthday suits. Watsu therapy takes place in an amazing pool filled by the adjacent lava tube. Meant to re-create the feeling of being in a womb, the hour-long therapy is essentially an underwater massage. You feel totally weightless, thanks to some artfully applied weights and the buoyancy of the warm salt water. It's a great treatment for people with disabilities that keep them from enjoying a traditional massage. The aesthetic treatments on the menu incorporate high-end products from Epicuran and Emminence, so a facial will have a real and lasting therapeutic effect on your skin. The spa also offers a full regimen of fitness and yoga classes, as well as more mainland-style procedures like Botox and Restylane injections.
Spa Without Walls at the Fairmont Orchid. This is possibly the best massage on the island, partially due to having the best setting. Massages at the Spa Without Walls are either facing the ocean or a waterfall. Though most people will probably opt for the ocean, both settings are absolutely peaceful. There are other great treatments as well, including facials, fragrant herbal wraps, and coffee and vanilla scrubs, but the massages are the best thing going.
Mandara Spa at the Waikola Beach Marriott Resort. A brand spanking new two-story spa overlooking the hotel's main pool with a distant view of the ocean, Mandara offers a very complete if not unique spa menu, with more available facial options than you'll find at the island's other spas. Mandara operates spas throughout the world and on a number of cruise lines, and they are managing this one for Marriott, using Elemis and La Therapie products in spa and salon treatments. The spa menu contains the usual suspects -- lomi lomi, a variety of facials, scrubs, and wraps -- but they do incorporate local ingredients where appropriate (lemon and ginger in the scrubs, warm coconut milk in the wraps), and the new facilities are beautiful.