The gates for the new locks have been built by subcontractor Cimolai and have travelled by sea from the port of Trieste in Italy to the waterway's Atlantic side on board the semi-submersible vessel STX Sun Rise.
The first four gates are 57.6m long, 10m wide and 30.19m high, and weigh an average of 3,100t. They will be installed in the middle chamber of the new locks in the Atlantic side.
"This is an exciting moment for the Panama Canal - the arrival of the new gates marks a great progress for this engineering project," said Panama Canal administrator Jorge Quijano.
The steel gates will be transported to their final position using the same self-propelled motorised wheel transporters (SPMTs) that are used to load and unload from the ship.
The new locks of the expanded Panama Canal have a total of 16 gates, eight for each new lock complex. The gates are being shipped four at a time from Italy. They will be unloaded onto a temporary dock until ready for installation. Unlike the current canal, which uses mitre gates, the expanded Canal will have steel rolling gates.
The Panama Canal Expansion is now 62% complete. It involves the construction of a third lane of traffic allowing the passage of post-Panamax vessels, which will double the canal's capacity.