The term for ships designed to transit the expanded Panama Canal is Neopanamax. It is also written “New Panamax,” referring to vessels sized for the canal’s larger third set of locks.
The expanded locks opened to commercial traffic on June 26, 2016. They increased the canal’s capacity beyond the original Panamax limits, allowing vessels up to roughly 366 meters long, 51.25 meters wide, and 15.2 meters in draft, depending on operating conditions.
Neopanamax ships are substantially larger than original Panamax vessels, but they are not the world’s largest ships. “Post-Panamax” describes vessels too large for the original locks; it does not specifically mean ships built for the expanded locks. “Suezmax,” meanwhile, is a separate size classification based on the Suez Canal.
The expansion changed shipping patterns by enabling more container, liquefied natural gas, and bulk carriers to cross between the Atlantic and Pacific. Ports also had to deepen channels and upgrade cranes to handle these larger vessels.