Prime Minister Stephen Harper told MPs Wednesday that HMCS Regina would be sent to join one of NATO's standing maritime groups.
"Our government and our country remains steadfast in our support for the people of Ukraine in the face of ongoing militarism and aggression by the Putin regime," he said.
An emailed statement to CBC News from the Department of National Defence said, "Canada has committed HMCS Regina to NATO Standing Maritime Forces as part of NATO's reassurance package.
"Canada is working with NATO authorities and our allies to determine how HMCS Regina will be employed and until this is complete we won't be able to state precisely where HMCS Regina will go or when it will depart the Arabian Sea to join a NATO fleet."
No other information was offered about the new mission or which specific NATO force HMCS Regina will join.
Mediterranean likely destination
NATO maintains four fleets of allied ships deployed on different missions in different regions. Two are focused specifically on counter-mine warfare, and the two others are assigned to anti-terror and counter-piracy operations.
Standing NATO Maritime Group 1 normally patrols the Mediterranean Sea and monitors shipping, "to help deter, defend, disrupt and protect against terrorist activity," according to NATO's website.
That group was recently reassigned to the eastern Mediterranean as part of NATO's new reassurance mission in response to Russia's annexation of Crimea and the buildup of troops along the Ukraine border.
That fleet, known by its acronym SNMG1, currently consists of two patrol ships, one each from Norway and Germany. The fleet is also often supported by various submarines and supply ships. It's likely HMCS Regina will join that group in the Mediterranean.
But that move will leave Canada's post in the Arabian Sea apparently vacant.
Regina has been at sea on that mission since January, but the Canadian navy has been a key part of the anti-terror fleet in the Gulf of Aden, Arabian Sea and Indian Ocean since ships were first deployed to the region following the attacks on New York and Washington in 2001.
Support for Ukraine
Yesterday, the Canadian government dispatched six CF-18 Hornet warplanes to Romania as part of the NATO mission.
The deployment marked a hardening of the government's commitment to worried new NATO members in Eastern Europe.
Wednesday, the government also announced three military members would be sent to Ukraine as part of a nine-member Organization for Security and Co-operation in Europe Directorate of Arms Control Verification mission.
The mission was requested by Ukraine and is, according to the government, being conducted "in order to dispel concerns regarding unusual military activities in Ukraine, and to ensure a continuous international military presence on the ground."
That mission runs until May 11.