By Moon Keun-sik

Published Jul 26, 2026, 9:30 am KST

The decision has been made. Canada has selected Germany over South Korea to procure 12 next-generation diesel-electric submarines. At this point, debating the winners and losers of the bidding process serves little purpose. Having served more than two decades as a submariner, my central concern is not the outcome of the procurement itself, but the type of vessels that will protect Canada's national security over the next 30 to 40 years.

Canada's current submarine force consists of four Victoria-class diesel-electric boats, acquired second-hand from the United Kingdom in the late 1990s and plagued by maintenance challenges throughout their service life. The 12-vessel replacement program represents the most significant expansion of Canada's undersea fleet in generations — and the platform chosen today will define Canadian submarine operations into the 2060s.

Submarines are not equipment that can be swapped out as easily as automobiles. Once a vessel is commissioned, it remains a vital national asset for nearly four decades. Procurement decisions, therefore, must be driven not by political calculations or shifting public sentiment, but by the operational environments and threats a country is realistically expected to confront.

The Australian Precedent

Canada's current procurement inevitably brings to mind Australia's Future Submarine Program of 2016. Canberra signed a contract worth approximately 40 trillion won to acquire 12 diesel-electric submarines from France. Yet within five years, Australia scrapped the agreement, helped establish the AUKUS security partnership with the United States and the United Kingdom, and pivoted decisively toward acquiring nuclear-powered submarines. Under the AUKUS Pillar I framework, the United States committed to selling Australia three to five Virginia-class nuclear-powered submarines beginning in the 2030s, with the United Kingdom and Australia eventually building a new SSN-AUKUS class.

Australia absorbed enormous financial penalties and diplomatic costs — including a damaged relationship with France — because it concluded that diesel-electric submarines alone could not adequately address the security challenges ahead. That lesson should not be lost on Ottawa.

Canada's Strategic Challenge

Canada confronts a remarkably similar strategic landscape. It must simultaneously secure the Pacific, Atlantic, and Arctic theaters while monitoring one of the world's largest Exclusive Economic Zones. As Arctic shipping routes gain strategic significance with the steady reduction of sea ice, the region is evolving into a major arena of military competition. Like Australia, Canada is a core member of the Five Eyes intelligence alliance alongside the United States, and through the North American Aerospace Defense Command (NORAD), the two countries share joint responsibility for continental aerospace and maritime warning.

Meanwhile, the Arctic is seeing a steady increase in Russian nuclear-powered submarine activity, part of a broader Russian military buildup that includes the reactivation of Soviet-era bases along the Northern Sea Route. If Canada intends to exercise effective sovereignty over its Arctic territories, it will require substantially stronger undersea operational capabilities than it currently possesses. Many missions essential to that objective, however, are exceedingly difficult — and in some cases effectively impossible — for diesel-electric submarines to execute.

Under-ice operations. In the Arctic, thick ice frequently makes snorkeling or surfacing impossible. Nuclear-powered submarines can remain submerged beneath the ice for months at a time, while diesel-electric submarines are ultimately limited by battery endurance.

Long-term tracking of hostile submarines. Shadowing Russian nuclear-powered vessels for days or even weeks demands sustained high-speed submerged operations. Diesel-electric submarines must periodically snorkel to recharge their batteries, increasing the risk of losing contact with the target.

Long-range land attack. Modern submarines have evolved into strategic platforms capable of launching cruise missiles at targets thousands of kilometers away. Nuclear-powered submarines hold a decisive advantage in their capacity to approach such targets covertly over vast distances and withdraw rapidly after completing a mission.

In short, many of the strategic missions Canada is likely to undertake in the coming decades are better matched to the capabilities of nuclear-powered submarines.

Addressing Nuclear Concerns

I fully appreciate that many Canadians are uneasy with anything associated with nuclear technology. Nuclear-powered submarines, however, should not be conflated with nuclear weapons. France already operates nuclear-powered submarines, and current reactor technology is steadily advancing toward the use of low-enriched uranium (LEU). The United States is also studying the feasibility of incorporating LEU into future naval reactor designs.

Nuclear-powered submarines fueled by LEU could thus represent a practical solution — one that minimizes nuclear proliferation concerns while delivering the operational capabilities these demanding missions require. This is a consideration of particular relevance for Canada as a staunch advocate of nuclear non-proliferation and a member of the Nuclear Suppliers Group.

Given these realities, Canada should reassess whether an all-diesel fleet of 12 submarines truly constitutes the optimal force structure. A potentially more effective approach would be a High-Low Mix: diesel-electric submarines for coastal defense and routine maritime patrols, complemented by nuclear-powered submarines for Arctic operations, long-range deployments, anti-submarine surveillance, and strategic land-attack missions.

A Message to Canada's Submariners

Above all, there is one message I wish to convey directly to the men and women serving aboard Canada's submarines.

Submarines are not operated by politicians — they are operated by submariners. Likewise, those who best understand the capabilities required for national defense are the sailors who crew these vessels every single day.

Military personnel are not expected to engage in partisan politics. It is, however, their professional duty to inform governments and legislatures what capabilities are genuinely necessary for national defense and to provide sound military advice. When the military remains silent, political considerations inevitably begin to shape military strategy, and the consequences can compromise national security for decades.

The Korean Experience

South Korea confronted a similar situation in 1996–97. As part of a Russian loan repayment arrangement, Moscow offered Seoul Kilo-class submarines on highly attractive financial terms. The Republic of Korea Navy nonetheless declined the offer, citing concerns over uncertain long-term logistics support, incompatibility with its existing German-designed submarine fleet, and the prohibitive costs of maintaining two separate submarine systems.

That decision ultimately enabled Korea to concentrate on German submarine technology, accumulate indigenous expertise, and develop into one of the world's leading submarine designers and builders. The professional judgment of operational experts at that time laid the foundation for today's formidable Korean submarine force.

Today, the Royal Canadian Navy stands at an equally consequential crossroads. Government policy rightfully commands respect, but decisions concerning the nation's future defense capabilities must also fully incorporate the professional expertise of those who will operate these systems. In light of the evolving strategic environment, the Royal Canadian Navy should continue presenting both the government and the Canadian public with a long-term vision for submarine force development — one that includes the eventual introduction of nuclear-powered submarines.

In this regard, Canada should also maintain close cooperation with South Korea, which is actively pursuing the development of LEU-based nuclear-powered submarines and possesses world-class submarine design and shipbuilding capabilities.

Australia's experience offers an unambiguous lesson: selecting the right capability from the outset is far less costly — and far more secure — than correcting the wrong decision years later.

Ultimately, submarines should be chosen not by politics, but by the operational environment. And no one understands that operational environment better than the submariners who stand watch beneath the sea in defense of their nation.

Ret. Navy Capt. Moon Keun-sik is an adjunct professor at the Graduate School of Public Policy, Hanyang University. He served as commanding officer of the Republic of Korea Navy submarine Na Dae-yong.