How to say "sea" in Japanese

• 海うみJLPT N5approx.Common
  nounThe everyday word for the sea or ocean as a body of water; the default choice in ordinary speech and writing whenever you simply mean the sea, neutral in tone.
  何なんとしても海うみをひと目めみたいものだ。↗

  I ache for a sight of the sea.
• 海洋かいようJLPT N2approx.Common
  nounThe same sea/ocean sense in a Sino-Japanese form, treating the ocean as a vast whole; typical of written, scientific, and official contexts rather than casual talk.
  ロブスターは海洋かいよう動物どうぶつの一種いっしゅに属ぞくします。↗

  Lobsters belong to a class of marine animals.
• 海原うなばらCommon
  nounA literary, poetic word for the open sea, evoking a broad expanse of water; at home in literature, songs, and descriptive writing, not in everyday reference to the sea.
• 海神かいじんCommon
  nounReally the name of a sea god of Japanese myth rather than a common noun for the sea; seldom the word you want when you mean the sea itself.

Use 海 for the sea in ordinary language, 海洋 in written, scientific, or official contexts, 海原 for poetic descriptions of the open sea, and 海神 almost never, since it names a sea god.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 海うみsea
• 海洋かいようocean
• 海原うなばらocean
• シーsea
• 海上かいじょう(on the) sea
• 海面かいめんsea level
• 海神かいじんsea
• 洋ようocean