Financial terms of the deal with Japan's Sumitomo Corp. and the Oshima shipyard weren't released.
Fednav said Thursday that the bulk carriers will reduce carbon emissions by 20 per cent.
"The environment is one of our top priorities when we consider the design of a new vessel for the Great Lakes," president and CEO Paul Pathy said in a news release.
"It is very important to us and also to our customers that our vessels not only respect but exceed environmental regulations in Canada and worldwide."
Fednav said the environmentally advanced vessels will become the flagships of its fleet of more than 80 ships. The new vessels will carry cargo through the St. Lawrence Seaway to and from Great Lakes ports and around the world.