The Seas and Oceans That Border Japan

An Island Nation Defined by Water

Japan's maritime boundaries shape its climate, economy, and security:

• Sea of Japan (East Sea) – West; separates Japan from Russia, North Korea, South Korea. Rich fisheries; disputed name.
• North Pacific Ocean – East; deep trenches (Japan Trench), Kuroshio Current, tsunami exposure.
• East China Sea – Southwest; continental shelf disputes (Senkaku/Diaoyu); major shipping lanes.
• Philippine Sea – South; part of Pacific; Mariana Trench, typhoon genesis region.
• Sea of Okhotsk – Northeast; seasonal sea ice; borders Hokkaido & Russia; rich fisheries.

Strategic Significance

• Exclusive Economic Zone (EEZ): ~4.5M km² (6th largest).
• Chokepoints: Tsushima, Tsugaru, Soya, Osumi Straits.
• Resources: fisheries, methane hydrates, rare-earth mud.

Japan's geography makes it a quintessential maritime nation—dependent on seaborne trade, vulnerable to ocean hazards, and active in ocean governance.