The construction company won the contract, which could be worth as much as $470 million when it's finally negotiated, according to a report by the Daily Journal of Commerce. Clark also built Concourse A in 2004, according to the DJC.
The design work hasn't yet been completed, but the plan is to have a 960-foot aerial walkway to access the terminal, where customers will be walking above the taxiing airplanes.
Work on the project is expected to begin in mid-to-late 2016 and major construction will begin in 2017, according to the report.
Seven gates will be added to the existing 11, and there will be two more baggage carousels, according to the DJC.
The decision over who will pay for the terminals has been a contentious one.
The total cost of the upgrade to the terminal could be more than $600 million. That cost would be covered by what's called "passenger facilities charges," or PFCs, essentially a per-head tax on passengers moving through the airport. These are a common way of paying for capital investments.
However, Alaska Air Group (NYSE: ALK) has balked at having to cover costs for the international terminal's upgrade, since so few Alaska customers use the facility. Alaska primarily flies domestically, while its main competitor at Sea-Tac, Delta, flies primarily internationally.
Alaska has said it doesn't want its customers to pay for a facility that will be used primarily by its chief competitor.