The new Spa at Marco Island Marriott was funded by Massachusetts Mutual Life Insurance Co., the owner of the property. Cornerstone Real Estate Advisers Inc. was Mass Mutual's adviser on the project. The spa was designed by Brennan Beer Gorman Monk/Interiors of New York and Smallwood, Reynolds, Stewart, Stewart & Associates Inc./Architects of Atlanta.

The spa has a traditional South Pacific design with a contemporary, sophisticated look throughout the interior, which uses textured teakwood, carved stone, ceramic, terrazzo and bamboo. The therapies are performed in twenty-four seaside, serene retreats. The fitness center includes cardio-vascular machines and offers yoga, water yoga, Pilates, spinning and other exercise classes. Men and women each have lounges and locker rooms with plunge pools, steam rooms and saunas. The spa also includes a 650-sf retail boutique.