Canada’s submarines are running out of time. Built over thirty years ago for service with the United Kingdom’s Royal Navy, the four-boat Victoria-class was acquired by Canada in the 1990s and has never quite lived up to its advertised potential. It now needs replacement, and submarine procurement programs can be long and uncertain ordeals. However, ever since former Prime Minister Justin Trudeau announced that Canada planned to pursue a fleet of up to twelve submarines in the summer of 2024, Canada’s submarine procurement is one project that has actually moved extremely quickly. Requirements were set, industry feedback sought, and the down-selection to two potential builders all took place in just over a year. By March 2026, both builders had submitted detailed bids, with Canada now potentially just weeks away from making its final selection.
The first submarine contending for the Canadian submarine contract is Hanwha Ocean’s KSS-III-class, already in service with the South Korean Navy. The second submarine in contention is TMKS’ Type 212CD-class, being built for Germany and Norway. The Government of Canada has stated that, notwithstanding the differences in their capabilities, sizes, and systems, both designs meet the Royal Canadian Navy’s needs, and the final decision will be based on how well the competing bids serve Canada’s industrial, diplomatic, and economic needs. One thing that both designs have in common is that they are diesel-electric submarines with an integrated air independent propulsion system—not nuclear powered.
Nuclear-powered submarines have a reputation for being the most advanced, most capable, submarines in the world. Nuclear submarines have real advantages over diesel-electric submarines that are relevant for Canada. Hence the question: why does the Government and Military of Canada appear to have no interest in nuclear-powered submarines for the Royal Canadian Navy?
The answer to this question comes down to what tasks are the highest priority for Canadian submarines and the real-world challenges of procuring nuclear-powered options. However, that does not mean nuclear-submarines do not have advantages.
The Advantages of Nuclear over Diesel-Powered Submarines
Generally speaking, nuclear submarines’ advantages are that they have enormous range without the need to refuel, can operate at higher top-speeds than conventional submarines, don’t sacrifice range to operate at those higher speeds, and that they can stay submerged for months without needing to exchange air with the surface. Discussions of submarines for Canada often centre around the Arctic, and all of these advantages of nuclear submarines are relevant to maintaining a persistent presence there.
Operating diesel-electric submarines is very difficult in the North because they need to exchange air with the surface to run their diesel generators that recharge their batteries. This air exchange is usually, and most safely, done with a snorkel, but sea ice makes this process a liability as snorkels cannot penetrate solid ice sheets and can be damaged in areas with loose ice chunks. Nuclear submarines do not have these concerns.
Canada’s Arctic also has no facilities capable of supporting submarines, and building such facilities has proven to be an immense challenge. Without support facilities in the North, the distances that Canadian submarines must transit—independent from support—to and from the Arctic can actually be greater than the distance to friendly ports in Asia or Europe, even if they never leave Canadian waters. The distances involved makes long range a requirement. The range necessary to patrol over these distances is possible for diesel-electric submarines, but only by working around limitations that do not exist for nuclear submarines.
Nuclear submarines’ higher speeds are also beneficial because it can increase patrol efficiency. More speed means less time transiting to a patrol area and more time where the submarine is needed, potentially allowing fewer nuclear submarines to provide equivalent coverage within the Arctic when compared to a diesel-electric fleet.
The advantages of nuclear submarines also apply beyond the Arctic. One of the main capabilities these submarines offer is the ability to threaten another country’s sea lines of communication—that is, the routes used by its trade and naval vessels. If Canada needed to threaten another country’s sea lines—unless that country were to be its long-standing treaty ally, the United States—geography dictates that it would be doing so a long way from Canadian shores. Significant range is thus a requirement for Canada to have this capability, with speed providing another benefit because it makes that threat more immediate. Nuclear submarines are better suited to this task than non-nuclear submarines. A similar logic applies to using submarines to threaten targets on land.
Nuclear-Powered Submarines and Canada’s Procurement Record
These advantages have historically been well understood within the Royal Canadian Navy and the Government of Canada. The current procurement project is only the third time Canada has sought to acquire new submarines since the first nuclear submarine, operated by the United States Navy, sailed in 1954. Although other options were executed in the end, one should note in both of the previous submarine procurement projects, the intention was, at least for a time, to acquire nuclear submarines.
In the 1950s, the Royal Canadian Navy selected the US Navy’s nuclear-powered Skipjack-class before the government overruled that plan and selected the United Kingdom’s non-nuclear Oberon-class in 1960 instead. In the 1980s, the Government of Canada under Brian Mulroney’s leadership announced that it would replace the Oberon-class with nuclear-powered submarines in its 1987 Defence White Paper. It would go on to reverse that decision in 1989, eventually acquiring the currently serving Victoria-class. Despite the result, in both cases, the advantages of nuclear submarines featured prominently in discussion and debate.
Nuclear submarines’ advantages of speed and range still exist today, and Canadians in and out of Government service show awareness of them. Public discourse on military subjects in Canada is often limited, but interest in nuclear submarines spiked after the United States, United Kingdom, and Australia announced the AUKUS pact in 2021. This agreement aimed to transfer several American nuclear submarines to Australia in the near term, with the goal of Australia one day being able to build its own nuclear submarines domestically. Many Canadians wondered why Canada could not be included in this agreement. A small, but loud, segment of public and academic Canadian defence communities have persisted in advocating nuclear submarines for the sake of their operational effectiveness as well as for deepening cooperation with such partners. Nonetheless, there have been no public indications that nuclear submarines were seriously considered by the RCN or the Government in this procurement.
Cost is undoubtedly a factor in this decision, but it is not a sufficient explanation on its own. Australia’s planned acquisitions under AUKUS gives us a good cost benchmark for Canada. That project is expected to cost up to $368 billion over the first 30 years—an average of $12 billion annually. This sum is enormous; it would consume nearly half of the defence budgets that Canadians are used to supporting. However, Prime Minister Mark Carney recently committed to increasing Canada’s defence spending to 3.5% of GDP by 2035. Based on current GDP figures, that represents $52.5 billion of additional annual defence spending over 2024 levels. Although some priorities will compete with one another, a $12 billion annual program is not inconceivable in that context, especially if it addresses a core need.
Rather than cost, Canada’s continued official disinterest in nuclear-powered submarines appears rooted in something Canadian defence discourse is not used to seeing: decision makers have today a deeper understanding of strategic and industrial considerations than in past procurement cycles.
Misunderstood Priorities
Canada’s nuclear submarine pursuit in the 1980s was based on an understanding of the advantages of nuclear submarines, but a misunderstanding of strategic priorities. The immediate catalyst that led to the decision to procure nuclear submarines was when an American Coast Guard icebreaker, the USCGC Polar Sea, sailed through the Northwest Passage without Canadian permission. The United States claimed the Passage as an international strait, giving it a right to transit. In response to public concern, the Mulroney Government quickly made it clear that Canada viewed the waters through its Arctic Archipelago as internal waters, with the implication being that permission was always needed for passage.
This position created a quandary for Canada since it did not have the ability to monitor violations of—much less enforce—these claims. Persistently monitoring the entire Canadian Arctic with ships, satellites, planes, or ground stations was impractical for technical reasons, and other countries would always know when these assets were absent. Submarines would have been an appealing solution as they could monitor ships without being detected themselves, forcing those ships to always act as if they may be surveilled even if the actual coverage was intermittent.
Since it would have been extremely difficult to operate diesel-electric submarines of the time in the Arctic, using “submarines” for the purpose of monitoring the Arctic meant acquiring “nuclear submarines”. Alongside some extremely optimistic estimates of the cost of the program and the likely interest of allies in assisting Canada, the Government demonstrated an understanding of this technical reality when it announced in its 1987 defence white paper that it would be acquiring nuclear submarines, distinguishing between them being the “best way to achieve the required operational capabilities in the vast Pacific and Atlantic oceans” and “the only vessel able to exercise surveillance and control in Northern Canadian ice-covered waters”.
While the technical judgement that nuclear submarines were the only tool to surveil and control Arctic waters was sound, the strategic decision to prioritize that goal was not. While there are justifications for a country to want to monitor and control all its territory, there is always going to be a hierarchy of priority based on different areas economic value, proximity to population and industrial centres, strategic utility, and diplomatic alternatives to military presence. For example, in any conflict with a major naval power, the first priority for Canada’s submarine force is unlikely to be the Arctic. The protection of shipping in the Gulf of St Lawrence, the Strait of Juan de Fuca near Vancouver, and the seas around Saint John, Halifax and Prince Rupert—near all of Canada’s largest ports—would almost certainly be a much higher priority.
This prioritization reflects a fundamental concept in military strategy referred to as a “centre of gravity”—which is the “hub of all power and movement, on which everything depends” according to famed strategist Carl von Clausewitz, and the “point against which all [of a belligerent’s] energies should be directed” in order to gain advantage and win in any conflict.
None of Canada’s centres of gravity—none of its most vital capital, industrial, resource, population, strategic, or trade centres—are in the Arctic. That is not to say that the Arctic does not have value in several of these areas, but the Arctic is not a hub that Canada relies on for its prosperity, ability to project military power overseas, or existence as a nation.
Canada’s major ports, on the other hand, are its centres of gravity, at least when it comes to conducting war on or across the ocean. Canada depends on the sea lines of communication that must start at its ports. Because these sea lines pass through very few chokepoints—and none that are likely to be unfriendly—except at entry points to the Indian Ocean, threatening Canada’s use of them can most efficiently be done close to these ports. Hunting vessels, even civilian vessels, in the high seas is resource intensive. The result is that Canada should expect them to be a high priority target for its adversaries.
History reinforces this perspective. During the Second World War, German U-boats operated near all of Canada’s major East Coast ports, as well as in the Gulf of St. Lawrence and even into the St. Lawrence River. A future adversary would likely seek to do the same with modern submarines on both coasts. Canadian military planners should take this seriously.
Taking the threat of enemy submarines in these areas seriously means prioritizing platforms which can deal with those threats most effectively. The best counter to a submarine is another submarine and, despite the advantages of nuclear submarines in other areas, diesel-electric submarines have the advantage here. That advantage comes down to noise profiles. Nuclear-powered submarines are always generating noise because they cannot shut down their reactors—they are always quiet, but never silent. Diesel-electric submarines, by contrast, can operate on batteries in near silence, giving them an advantage. This advantage is lost when they must periodically use diesel generators to recharge, to be sure. However, this is less of a liability near home, where they can return to port or arrange support from other assets during this time of vulnerability.
Without another solution to the Arctic monitoring issue, perhaps one can argue that a nuclear submarine that was less capable in providing security near Canadian ports, but could be used in the Arctic—as opposed to a diesel-electric submarine that was the best submarine for maintaining security near ports, with very little Arctic utility—would be a reasonable trade-off. Nevertheless, the Arctic issue was primarily one that should have been addressed through diplomatic means, as evidenced by the fact that it eventually was. In 1988, the United States and Canada agreed that American ships would not transit through the Northwest Passage without Canadian permission, even as the United States would not recognize Canada’s claim that it was internal waters. With few other countries having the means or interest to sail through the area—the Soviet Union, being the main contender, actually supported Canada’s claims—the matter was settled. Canada could thus abandon its nuclear submarine plans the following year.
The Current State of Play
Today, with receding ice sheets and greater industrialization around the world, more countries may have both the means and interest in using the Northwest Passage for passage. However, Canada has made real progress in having its claims recognized internationally, while new technologies provide options other than nuclear submarines for monitoring the area. Cheaper satellites, and modern over-the-horizon radars are two such technologies. A third is the air independent propulsion (AIP) systems found on many modern diesel-electric submarines—including the two Canada is considering.
AIP systems began being used on naval submarines in the 1990s, not long after the Victoria-class was completed without them. They come in a number of varieties, but their commonality is that they give diesel-electric submarines the ability to generate electricity for extended periods of time without relying on their diesel generators and without exchanging air at the surface—sometimes extending the time a diesel-electric submarine can remain fully submerged from a few days to several weeks.
This largely addresses the main barrier to diesel-electric submarines operating in the Arctic: the need to frequently snorkel. With the ability to remain submerged for weeks, they can confidently enter ice-covered areas and return to ice-free ones when required. The technology does not make them the equal of nuclear submarines in every respect. Their sustained speed while using AIP is limited, for example. However, since noise considerations force even nuclear submarines to primarily operate at low speeds, with the option to sprint at higher ones in emergency, and diesel-electric submarines with AIP can mimic this behaviour by idling to charge their batteries and sprint by drawing them down, this is less of a tactical difference than it may appear.
AIP systems do have the disadvantage that they cannot be regenerated at sea. A ship with 21 days of AIP when it leaves port only has those 21 days to use until it refuels. Once that time is used up, they must rely on more frequent charging cycles until they return to port or refuel from another ship carrying specialized re-agents. However, even at the reduced speeds AIP is limited to, 21 days is enough for a submarine to patrol from the most southerly winter extent of the Arctic ice sheet to the most northern point of Canadian territory and back. This will rarely, if ever, be done since the ability of nuclear submarines to harm Canada from these locations is limited, and nothing else is likely to be present. But just having the option accomplishes many of Canadian goals that previously only nuclear submarines could achieve, as other countries will need to guard against the possibility.
More commonly, when deployed to the Arctic, Canadian AIP submarines will be used along the shipping channels that open in the Arctic during the winter, monitoring traffic and, in conflict, hunting belligerent submarines that are actually a threat to that shipping. Their under-ice capability will mostly be used to transit from one area of open water to another or deprive nuclear submarines of the safety they might otherwise find under ice near these shipping channels. These are the highest priority activities in the Arctic.
Submarines with these systems are also capable of other roles. The presence of diesel-electric U-boats on Canada’s East coast during the Second World War shows that threatening shipping on the far side of oceans has long been within diesel-electric submarines’ capabilities. AIP systems just make them more survivable when far from home. Diesel-electric submarines may not be able to independently threaten shipping as persistently as nuclear submarines, but that can be addressed by accessing nearby friendly ports, and Canada is unlikely to be intercepting shipping except in support of allies. Similar logic applies to the option to attack high-value land targets with submarines. AIP equipped submarines may still be at a disadvantage in this work compared to nuclear submarines, but they have a basic capability that meets Canada’s needs.
The reason Canada can accept a lesser capability when operating in the Arctic, disrupting shipping, or attacking land targets is because these are all secondary considerations for Canada’s submarine fleet. The most important missions for Canadian submarines will happen near major ports, where diesel-electric submarines already had an arguable advantage over nuclear submarines. The ability that AIP submarines have to go for weeks without recharging after leaving port amplifies this advantage over nuclear submarines significantly. Put together, the increased advantage of diesel-electric submarines with AIP systems over nuclear submarines in Canada’s most critical area of need, and their ability to perform a wide range of secondary tasks, eliminates most of the strategic arguments that could be made for Canada to acquire nuclear submarines in the present-day.
The nail in the coffin today for a Canadian acquisition of nuclear-powered submarines, however, remains what it was in the 1980s: Canada has no option that will allow it to acquire them. Not on the necessary timelines, at least.
Among Canada’s three allies who operated nuclear submarines in the 1980s, the United Kingdom and France were, at best, luke-warm to the idea of Canada acquiring them, while the United States was outright hostile.
America’s hostility had three basic causes. First, it was clear that Canada’s desire for nuclear powered submarines was in response to US actions—treating the US as a potentially hostile nation—and it’s natural that they wouldn’t want to provide their own foil. The US also believed that Arctic waters held modest strategic importance, and worried that Canadian investment in nuclear submarines would impact the force that it could afford to sustain in the more strategically important European theatre. Finally, while the Northwest Passage was not of huge strategic importance as an international strait at the time, other international straits held and hold enormous strategic importance, and the precedent of one international strait becoming internal waters could open the door to the owners of other straits being similarly reclassified.
The United Kingdom and France’s lukewarm attitude was a result both of their disbelief that Canada would follow through, and of the concerns of the United States. The United Kingdom, in particular, operated its nuclear submarine program in close cooperation with the United States and couldn’t export its submarines or expertise without American approval.
America’s disapproval was less of a binding constraint—but still a factor for consideration—for France. However, their submarines of the time were significantly inferior in capability and not truly suitable to Arctic operations in any case.
This lack of an enthusiastic partner posed a major challenge to Canadian ambitions. Nuclear submarine technology has only truly been developed independently once—by the United States. All other operators were assisted in their acquisition either through espionage (USSR), open cooperation (United Kingdom and China), secret cooperation (France), or a lease arrangement (India). It is an extremely difficult technology to develop.
Nevertheless, Canada did consider developing its own nuclear submarine. One novel proposal was for a submarine that operated off of batteries, like a conventional submarine, but had a low-power Slowpoke-2 nuclear reactor onboard to recharge those batteries during periods of low activity without surfacing. It wouldn’t be able to operate continuously at full power like other nuclear submarines, but it also wouldn’t need to surface to charge its batteries like a conventional submarine. This may have been the kernel of a good idea—it’s very similar in concept to how modern air independent propulsion systems work—and can be lauded for realistically acknowledging some of Canada’s technical limitations, but it still wasn’t very realistic.
Canada not only had no experience building nuclear submarines, it had no experience building any sort of submarine; not since it had assembled a few for the United Kingdom during World War One. Modern submarines rely on a number of highly specialized systems—such as acoustic sensors and noise suppressions systems—that are immense engineering challenges which Canada would need to overcome on its own. Even with a less ambitious reactor concept, it could take decades and multiple iterations before a submarine that satisfied Canadian needs could be built domestically. As a point of comparison, France commissioned their first nuclear submarine in 1971. But their designs were consistently viewed as being behind their contemporaries until their fourth blank-sheet design—the Suffren-class—entered service in 2020. That 50-year timespan is a realistic expectation for a newcomer to develop competitive nuclear submarines.
In the end, this would always have made it impossible for Canada to acquire nuclear submarines in the 1980s. No other operator of nuclear submarines wanted to, and was capable, of giving Canada the assistance required. And developing the capability independently over decades did not meet Canada’s needs. Similar dynamics apply to Canada’s position with its allies today, with time pressure being created by the fact that Canada needs a replacement in service by the time the Victoria-class will be retired in 2035, and no one with both the willingness and capability to help.
Why not, then, partner with the United States and the United Kingdom? After all, those two countries are both working with Australia to meet its nuclear ambitions through AUKUS—with the first submarines expected to be in service in the early 2030s. Canada is a similar sized nation to Australia, with similar (or even closer) relationships with the United Kingdom and United States. This could suggest that Canada might pursue a similar arrangement and timeline. However, this concept falls apart on closer examination.
The logic behind AUKUS is built on Australia’s location. It is not just an agreement for the United States and United Kingdom to sell nuclear submarines to Australia in the near term, and help Australia build its own nuclear submarines in the long-term. It also includes the right to base their own nuclear submarines in Australia—with Australia bearing the cost.
Australia is much closer to where the United States and United Kingdom want to deploy their submarines in the Indo-Pacific than their own shores are. Basing their submarines in Australia reduces transit time, allowing their submarines to sustain similar “on-station” time even if they are operating fewer of them. Both the United States and United Kingdom have severe limits on their capacity to build nuclear submarines, arguably not even having sufficient capacity for their own needs. It’s only through the fact that this basing agreement reduces the number of submarines they need to operate that any of their submarines are freed up for sale to Australia. Canada does not have this leverage. Nothing Canada can do reduces the number of submarines the United States or United Kingdom require.
Australia is also expected to contribute significantly to the design process of a new AUKUS-class of submarine, which will be the United Kingdom’s next nuclear submarine and will serve as the design that’s eventually built in Australia. Australia can contribute to this because it gained significant experience building, and later upgrading, its current class of submarines—the Collins-class—in the 1990s and early 2000s. The Collins-class incorporated some truly world-beating innovations, and sustained a capable submarine industry. Canada, as an operator of submarines that were originally designed and built in the United Kingdom, can’t provide a similar contribution.
The reasons why Canada could not rely on the United States or United Kingdom to develop a nuclear submarine capability in the 1980s remain operative. At best, Washington still views the acquisition of nuclear submarines by Canada as a project that will drain resources from areas where they would prefer for us to invest. At worst, they still view it as a hostile action targeted directly at their interests. The United Kingdom is too integrated in the US program to support Canada independently. Even if London and Washington were convinced to help Ottawa to acquire nuclear submarines, the timing is impossible. AUKUS was created in 2021. Even if Canada could proceed on the same timeline, starting now would likely push receipt of the first submarine past the 2035 deadline. A similar timeline could only be achieved if AUKUS was abandoned and Canada effectively took Australia’s place in a similar agreement on an aggressive timetable. Otherwise, American and United Kingdom capacity to assist Canada will not exist until after much of what AUKUS promises has been delivered, well into the 2040s. That is too long for Canada to wait.
That leaves France as a potential partner. However, while France’s nuclear submarines are no longer significantly handicapped compared to those of the United States or United Kingdom, their ability to help Canada meet its timelines is no stronger.
France’s capacity for building nuclear submarines domestically is limited and appears entirely utilized for their own purposes well past 2035. If Canada were to pay for it, new capacity could plausibly be built. That would be a decade-long project itself, and with the typical construction time of a nuclear submarine in France of over nine years, that also pushes the first delivery well into the 2040s. One might consider the possibility of France helping Canada build nuclear submarines at home, but that has even longer timelines. Brazil is currently pursuing the domestic construction of a nuclear submarine with France’s assistance. That submarine was ordered in 2008. It is currently expected to launch in 2037, a 29-year delivery timeline. Far too long for Canada to consider that route for its next generation of submarines.
Conclusion
Canada’s decision not to pursue nuclear submarines is not the result of a single constraint, but the convergence of several. Canada’s highest priority missions for submarines, the raison d’etre of its fleet, are best served by diesel-electric submarines with integrated air independent propulsions systems—exactly what it is pursuing. The technologies that once made nuclear propulsion uniquely suited to Arctic operations are no longer the only way to operate in that environment. Though nuclear submarines still offer advantages in range, speed, and endurance, those advantages are most relevant when operating independently far from home, while Canada is only likely to act in those places with allies. Simply put, there is no viable path to acquiring nuclear submarines on the timelines Canada requires, whether through allies or domestic development.
Canada thus has a clear choice. Rather than pursuing the most capable submarine in abstract terms, Canada is pursuing the most appropriate one for its real-world purposes—aligned with its geography, its alliances, and its strategic priorities. Nuclear submarines remain powerful and, in some respects, unmatched tools. However, they are tools designed for a different set of problems than the ones Canada faces. The absence of a nuclear option in Canada’s current procurement is not an oversight. It is the result of a clear-eyed assessment of what Canada needs its submarine force to do, and what it can realistically deliver.
Image Credit: U.S. Navy photo by Chief Mass Communication Specialist Josh Thompson.
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