Premier Kathy Dunderdale of Newfoundland and Labrador praised the Comprehensive Economic and Trade Agreement for eliminating tariffs in the seafood industry.
Dunderdale says the deal will make it easier for the fishing industry to access the lucrative European fish and seafood market, while removing duty on certain fish products.
She says that once the agreement is implemented in 2015, it could create new opportunities worth more than $100 million to the industry.
"This is a great day for Newfoundland and Labrador, and a milestone achievement in our province's history," Dunderdale said in a statement.
"We will now have secured unrestricted access to markets in the European Union, which represents a game-changing development for the fishing industry in Newfoundland and Labrador. This is the most positive development in the fishing industry in decades, and will enhance prosperity in the industry and in our rural communities for years to come."
She said the agreement would be especially beneficial to the crab and shrimp industries.
New Brunswick Premier David Alward said the agreement could benefit the seafood and forestry industries in his province, but he has concerns about the possible impact on the pharmaceutical and prescription drug sectors.
"Overall, we feel positive if you look at the opportunities for Canadian companies and consumers to ultimately have access to the world's largest overall economy, that's a tremendous opportunity," he said in an interview.
"We believe there are positive things in there for New Brunswick, like our seafood sector, like our forestry sector for examples."
George Webster, the deputy premier of Prince Edward Island, said he expects the deal will provide benefits to the province's agriculture and fish sectors. He added that he recognizes it could have an impact on the provincial dairy industry and the costs of some prescription drugs, but he is hopeful that can be resolved.
"We look forward to working with the federal government to mitigate the potential impact on the dairy industry and in regards to drug costs," Webster said in a news release.
"I anticipate we will see this open trading relationship set the stage to attract investment into the province of P.E.I. and encourage further partnerships between the Island and the member states of the European Union."
Prime Minister Stephen Harper announced the agreement-in-principle Friday in Brussels, saying it should allow the free the movement of goods, services, investment and labour.