Four of 16 sluice gates have arrived at the Hidroeléctrico Reventazón project.
The gates will be used to control the flow of water through a series of diversion tunnels that will supply generating turbines.
The Instituto Costarricense de Electricidad said that the metal gates were made in Jiajing, China, under a deal with a company there that won the job with competitive bidding.
The state company said that six months will be required to install the gates.
The hydo project is supposed to be online next March and supply enough electricity for half a million homes.
The 12 additional sluice gates are still en route to a Chinese port, officials said. The company sent engineers to China to check on the fabrication of the gates.