The Starwood Hotels & Resorts group has announced that eight more of its luxury spas are to become members of The Starwood Spa Collection.

The collection comprises nearly 40 hotels and resorts in 18 countries and focuses on premier spas which become members of the group based on a number of criteria including the client service and treatments on offer.

The newest members include the St Regis Resort, Bora Bora in French Polynesia; The Wigwam Golf Resort in Arizona, US; Convento do Espinheiro Heritage Hotel and Spa in Portugal; The Westin Casuarina Hotel Casino and Spa in Las Vegas, US; and the Sheraton Colonia Golf and Spa Resort in Uruguay.

The spa development and marketing director of Starwood’s luxury spa brands, Mia Kyricos, said: “The spa collection features some of the world’s most renowned spas and we are honoured to welcome our new members to be part of the prestigious collection. The continued growth and evolution of this collection truly represents Starwood’s ongoing transition from real estate company to a world-class lifestyle brand.”

Photograph: The spa at The Westin Casuarina Hotel Casino & Spa, Las Vegas