The deal also covers related beauty, wellness and medi-spa services, including acupuncture and dermal fillers, as well as Elemis skincare and body products for ships currently sailing and all vessels that come into service for Norwegian during the agreement term.
Norwegian Escape and Norwegian Bliss are due for delivery in 2015 and 2017.
'We are very excited to announce this eight-year extension of our long and mutually rewarding relationship with Norwegian Cruise Line,' said Leonard Fluxman, president and ceo of Steiner.
Norwegian facilities include spas under Steiner's Mandara brand, the spa suites program on Norwegian Getaway, Norwegian Breakaway and Norwegian Epic, and spa services within The Haven by Norwegian, the line's suite complex.