The deal will see the Glasgow business, headed by group managing director Alister MacDonald, supply and install spa thermal and pool facilities at each location.
The Bahrain project, which starts in October and involves staff being on site for around six months, will be Barr + Wray's first in that country. It is part of a 50-storey 263-bedroom Four Seasons hotel complex on an oval- shaped island site in the Bahrain Bay development area.
Work on The Four Seasons Resort Dubai, located on the Jumeirah Beach, has already started, with the contract due to be completed early next year.
Peter Rietveld, managing director at Barr + Wray Dubai, said: "It is very exciting to be entering a brand new market in Bahrain on a project with such a well respected hotel group.
"Barr + Wray has already provided spa facilities for Four Seasons in London and Baku and we are looking forward to adding these new spas to our portfolio. The fact that we are securing high value contracts with renowned clients shows the level of business opportunities available out here in the Middle East."
Accounts for Barr + Wray for the 12 months to September 30, 2012 showed an 11% rise in turnover from £14.1 million to £15.6m with operating profits going from £1.04m to £1.32m.
At the end of 2012, Barr + Wray announced it had won a £4m contract to install swimming facilities at the new Center Parcs resort in Bedfordshire, which is scheduled to open in spring next year.