The Port and Airport Research Institute engaged in the routine statistical analysis on waveforms acquired through the Nationwide Ocean Wave Information Network for Ports and Harbours (NOWPHAS) from 1970. The network has wave gauges on 20–50 m deep seabed and GPS-mounted buoys at 100–400 m deep sites over Japan. This paper summarizes the half-century-long history of the network, the data processing procedure, and major statistics by referring recent ISOPE conference papers and conducting additional wave data analysis.