FnetPy is a Python package to request seismic waveform data from NIED F-net.

pip install https://github.com/seisman/FnetPy/archive/master.zip

from FnetPy import Client
from datetime import datetime

starttime = datetime(2011, 1, 2, 5, 10)
client = Client(username, password)
client.get_waveform(starttime, duration_in_seconds=300)