Two further options are being considered for the Corrib gas pipeline.
Shell says the new routes are variations on the two previously shortlisted options for bringing gas ashore in Co Mayo.
One would limit the distance the pipeline crosses unspoiled bogland in Rossport, while the other would mean a shorter route through Sruwaddacon Bay.
Both are further away from housing than the original proposal.
Vested interests in the area have until January 18 to make submissions on the new routes.