Celebrity Summit underwent a major refurbishment at Grand Bahama Shipyard as part of Celebrity Cruises' $16 million modernization program for Celebrity Summit and Celebrity Infinity. The project introduced the Rooftop Terrace on Deck 12, featuring cabanas, modular lounge furniture, decorative lighting, an outdoor movie screen and surround sound. The Normandie specialty restaurant was converted into Tuscan Grille, while Penthouse and Royal Suites received new furnishings, carpeting, curtains, bedding and upgraded bathrooms with marble finishes. The Solarium was renovated with new flooring, furniture and refinished pool surfaces, and the Spa Café received updated finishes. Additional improvements included an enclosed portrait studio, a dedicated future cruise sales office, casino renovations and removal of themed décor. Technical work included extensive hull and topside surface treatment and stabilizer overhaul. The shipyard also fabricated and installed a new steel accommodation block on Deck 5 containing 16 crew cabins, with some interior outfitting continuing after the vessel returned to service.

Celebrity Summit completed an extensive three-week transformation at Grand Bahama Shipyard as part of Celebrity Cruises' $140 million “Solsticizing” fleet-renewal program. The project added 60 new staterooms and introduced 107 AquaClass accommodations with access to the new Blu specialty restaurant. New Solstice-class venues included Qsine, Bistro on Five, Café al Bacio and Gelateria, Cellarmasters, Celebrity iLounge, and the redesigned Martini Bar and Crush. Celebrity Suites received new private verandas, while suites and existing staterooms were extensively refreshed with new carpeting, furnishings, upholstery, bedding and flat-screen televisions. Public areas throughout the ship received new décor, carpeting and upholstery inspired by Celebrity's Solstice-class vessels.

Celebrity Summit underwent a scheduled refurbishment at Blohm+Voss in Hamburg, Germany, involving the installation of new diesel-powered electrical generators designed to supply electricity while the ship was in port, reducing fuel consumption associated with its existing power-generation systems. The project also included classification-related inspections and technical maintenance. Passenger-area improvements included replacement of the flooring in the Rendezvous Lounge, refurbishment of the boutique and gift shop area, and refinishing of wooden railings throughout selected public spaces. The ship returned to passenger service on April 29, 2008, beginning its European cruise season.