STX France has started construction of Royal Caribbean International's fourth Oasis-class cruise ship with the steel cutting ceremony held at its shipyard in Saint-Nazaire, France. Royal Caribbean's third Oasis-class vessel, which is as yet unnamed, is currently under construction at STX France shipyard and the cruise operator awarded the order for the fourth vessel in May last year. Both the third and fourth Oasis-class ships will feature a split superstructure design, 16 decks with 2,700 staterooms, an 82ft-long zipline, a hand-crafted carousel, the Rising Tide elevating bar, the AquaTheater high-diving performance venue and a Central Park with more than 12,000 live trees and plants. The vessels will also offer facilities such as twin FlowRider surf simulators, cantilevered whirlpools, an ice-skating rink and the H2O Zone kids aquapark. In addition, passengers will benefit from the Royal Promenade, an interior boulevard with restaurants, lounges and boutiques, among others. Delivery of the third ship is scheduled for early 2016, while the fourth vessel is expected in 2018. Royal Caribbean's first Oasis-class vessel, Oasis of the Seas, was delivered in 2009 and the second ship, Allure of the Seas, started operating in October 2010.

A ship builder walks past a section of the Oasis Class 3 cruise ship at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. The Oasis-class III vessel is scheduled for delivery in mid-2016. (Photo by Stephane Mahe/Reuters)

Ship builders work on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

Ship builders work on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

Ship builders work on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A ship builder works on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A ship builder works on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A ship builder works on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

Indications are pictured on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A view shows on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

Ship builders work on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A ship builder works on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

Ship builders work on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

Ship builders work on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A ship builder works on a section of the Oasis Class 3 cruise ship at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

Ship builders walk past a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A view shows a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A ship builder cycles past a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A ship builder works on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

Ship builders work on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A ship builder works on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A ship builder works on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A view shows a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)

A ship builder works on a section of the Oasis Class 3 cruise ship under construction at the STX Les Chantiers de l'Atlantique shipyard site in Saint-Nazaire, western France, February 17, 2015. (Photo by Stephane Mahe/Reuters)