Navy comparison: 
Japan vs 
South Korea
Japan operates a fleet of 158 ships compared to 156 for South Korea. Of these, 158 and 155 are in active service respectively.
SEAS (Sea Equipment Aggregate Strength) Index face-off Full ranking →
JapanWorld #4
61.7
SEAS Index / 100
Japan leads overall, ahead on 3 of 8 categories
South KoreaWorld #6
50.8
Japan
South Korea
Bars: weighted contribution to the SEAS Index (hulls × category weight) · figures: active hulls at each side's latest inventory year · Methodology
Key figures as of 2026
| Japan | South Korea | Ratio | |
|---|---|---|---|
| Official name | Japan Maritime Self-Defense Force | Republic of Korea Navy | |
| Total ships | 158 | 156 | 🇯🇵 ≈ |
| Active ships | 158 | 155 | 🇯🇵 ≈ |
| Submarines | 23 | 22 | 🇯🇵 ≈ |
| Principal surface combatants | 52 | 31 | 🇯🇵 1.7× |
| Aircraft carriers | 2 | 0 | 🇯🇵 |
| Amphibious ships | 3 | 21 | 🇰🇷 7.0× |
Show full breakdown · 4 more rowsHide the 4 extra rows
| Corvettes | 0 | 5 | 🇰🇷 |
| Patrol boats | 6 | 35 | 🇰🇷 5.8× |
| Mine warfare | 18 | 23 | 🇰🇷 1.3× |
| Auxiliaries | 54 | 18 | 🇯🇵 3.0× |
Backbone classes one per tier held
Analyst Assessment
Run the wargame simulation →Verdict
Edge: Japan
Japan's Maritime Self-Defense Force holds the clearer overall edge over the Republic of Korea Navy, on the strength of 52 principal surface combatants, two Izumo-class carriers converted for F-35B operations and 23 conventional submarines built to a sustained one-boat-a-year rhythm. South Korea leads decisively in amphibious lift and coastal forces, and is closing fast in surface quality, but its 13 destroyers and single-theatre basing leave it the more regionally focused fleet.
Domain by domain
Surface combatants
Edge: Japan
🇯🇵 Japan52 principal combatants: 42 destroyers including Aegis-equipped BMD ships, nine Murasame-class and ten new Mogami-class multi-mission frigates. Deep Aegis and ASW specialisation, standardised hulls, high sensor and datalink integration.
🇰🇷 South Korea31 principal combatants: 13 destroyers, headed by six Chungmugong Yi Sun-sin-class and the Sejong-class Aegis ships, plus 18 frigates (eight Daegu, six Incheon) and five ageing Pohang corvettes. Modern but numerically thinner.
Submarines
Edge: Japan
🇯🇵 Japan23 boats, led by 12 Sōryū-class with AIP and lithium-ion batteries on later hulls, backed by eight Oyashio-class. Long-endurance, deep-water ASW and choke-point patrol doctrine with continuous domestic production.
🇰🇷 South Korea22 boats: nine Chang Bogo (Type 209), nine Son Won-il (Type 214, AIP), plus indigenous KSS-III units with vertical launch. Near-parity in numbers, growing indigenous design depth, shorter operating radius.
Carriers & naval aviation
Edge: Japan
🇯🇵 JapanTwo Izumo-class flight-deck ships modified for F-35B short take-off operations, giving organic fixed-wing air power at sea alongside a large rotary-wing ASW force.
🇰🇷 South KoreaNo carriers on file. Naval aviation is helicopter- and land-based; the projected light carrier concept remains unfielded, leaving fleet air defence dependent on Aegis destroyers and shore-based aircraft.
Amphibious & expeditionary
Edge: South Korea
🇯🇵 JapanThree Osumi-class LSTs supporting island-defence and rapid-deployment brigade lift; capable but a small, single-class force sized for reinforcement rather than assault.
🇰🇷 South Korea21 amphibious vessels, including Dokdo-class LPHs and 11 Solgae-class air-cushion landing craft, structured for opposed landings and peninsular manoeuvre. Clear advantage in lift and ship-to-shore connectors.
Coastal & mine warfare
Edge: South Korea
🇯🇵 Japan18 mine warfare units, including six Sugashima-class, and six Hayabusa missile patrol boats — a compact force focused on clearing approaches to home ports and straits.
🇰🇷 South Korea23 mine warfare vessels plus 35 patrol boats, notably 18 Yoon Youngha and 16 Chamsuri PKMR-211 craft, tuned to littoral defence and northern limit line contingencies.
Wildcards
- Basing and geographic reach Japan lists six bases spanning Yokosuka to Ōminato plus a facility at Djibouti, supporting sustained out-of-area deployment. South Korea's two bases, Busan and Jeju, concentrate its fleet around a single peninsular theatre.
- Shipbuilding and industrial depth Both sustain full domestic warship and submarine production. South Korea's commercial yards give greater surge capacity and export experience; Japan's programmes are steadier but narrower, tied to a small set of prime contractors.
- Alliance integration Both are US treaty allies with Aegis-compatible combat systems. Japan's interoperability extends to ballistic-missile defence and long-established co-located US naval forces at Yokosuka and Sasebo.
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Editorial assessment produced from the figures on this page and public sources; it is an informed reading, not a military assessment or a prediction.
Frequently Asked Questions
Which country has more naval ships, Japan or South Korea?
Japan has a larger navy with 158 ships compared to South Korea's 156 ships.
Which navy has more submarines, Japan or South Korea?
Japan operates more submarines with 23 compared to South Korea's 22.
Which country has more aircraft carriers, Japan or South Korea?
Japan has 2 aircraft carrier(s) compared to South Korea's 0.
Which navy has more destroyers, Japan or South Korea?
Japan operates 42 destroyers compared to South Korea's 14.
Which navy has more frigates, Japan or South Korea?
South Korea operates 18 frigates compared to Japan's 10.