Groupe Orleans Express said it would shut down the service by Nov. 30, citing its struggles with mounting losses.
"It is well-known that Acadian has been struggling financially for quite some time," Groupe Orleans Express CEO Denis Andlauer said in a statement late Tuesday.
"We've worked hard over the last few years to try to implement a sustainable network, to gain flexibility in the regulatory and operational framework and obtain support to allow us to reduce our financial losses but to no avail."
Andlauer said the company lost close to $12 million since it acquired the bus service in 2004.
Acadian Coach Lines runs buses in New Brunswick, Prince Edward Island and Nova Scotia. It has exclusivity on the routes it operates.
The company says that allows profitable routes to compensate for those that don't make money, particularly those serving communities with small populations. But Andlauer said the costs of operating the non-profitable routes proved too great.
"Sadly, we've exhausted all other alternatives and we have no choice but to close our Maritime operations. The decision to cease our activities has been a very difficult one and it was only taken after having rigorously evaluated every alternative and explored all scenarios."
Glen Carr, a spokesman for a union representing workers who run the New Brunswick and Prince Edward Island routes, said the way the company handled notifying employees of the closure was "disgusting."
"Our employees and membership were told around 4:15 p.m. that there was a conference call, but not all of them were told," Carr said in a phone interview from Sussex, N.B.
"They have no people skills at all and they left this dysfunctional management team running this company into the ground, and it serves them right."
Carr said he fears Groupe Orleans Express will open another company in Quebec and pay Quebec-based drivers to make the runs through New Brunswick, P.E.I. and Nova Scotia.
But Denis Gallant, vice-president of Acadian Coach Lines in the Maritimes, called Carr's comments "completely untrue."
"A problem with the network is a problem with the network, that doesn't change," said Gallant in a phone interview from Moncton, N.B.
Carr said the union will meet soon to decide their next move.
"How do you go to work tomorrow? Why would you go to work for this company that told you, 'No, here's a kick in the teeth, see you later,'" he said.
Gallant apologized to riders who will now be left without an intercity bus service.
"We are heartily sorry," said Gallant. "We do apologize that it has unfortunately come to this. It's definitely not a decision we took lightly."
Gallant said 120 workers would be laid off in total as a result of the shutdown.
In May, unionized workers for Acadian Coach Lines in New Brunswick and P.E.I. ratified a deal to end a lockout that halted bus operations for five months.
Acadian Coach Lines was founded in 1937. It is the largest intercity bus line in the Maritimes and also provides parcel service.