Under the approximately €400m contract, the two companies will deliver 16 turbine components and generators for the project, and will also operate a dockside Turbine Assembly Plant in Wales that will employ an initial 100 skilled workers.
Scheduled to begin commercial operation in 2019, the project will feature 16 bidirectional turbines, which will be manufactured by GE at its Rugby facility.
Located in the Severn Estuary, the tidal lagoon hydropower plant is expected to provide clean, renewable, and predictable power for over 155,000 homes.
Welsh Secretary Stephen Crabb said: "This project, if planning consent is granted, has the potential to transform the South Wales economy by creating hundreds of jobs and countless supply chain opportunities for local businesses across the region."
Tidal Lagoon Power CEO Mark Shorrock said: "We are now well placed to meet the targets we set ourselves for 50% of the capital expenditure for the Swansea Bay Tidal Lagoon to stay in Wales, rising to 65% for the UK as a whole.
"The project will lay the strongest possible foundations for a brand new industry in which Britain can lead the world.
"Together, we have iterated a bespoke turbine design for Swansea Bay that delivers 93% efficiency on the ebb tide and 81% efficiency on the flood tide."
