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N4Lesson notes · Oct 4, 2026

Forever in Japanese: 永遠えいえん (えいえん), ずっと, いつまでも, and ズッ友とも

"Forever" in Japanese is 永遠えいえんに (えいえんに) in songs, vows and anything grand, and ずっと in everyday conversation. "Let's stay together forever" is ずっと一緒いっしょにいようね, and "I'll love you forever" in a song is 永遠えいえんに愛いとしてる.

Learners often look up "forever", find 永遠えいえん, and use it everywhere. It is correct, but in casual speech it sounds like a song lyric. Most real "forever" sentences use ずっと, a small, everyday word that also means "all along" and "the whole time". This post covers both, plus いつまでも, 永久えいきゅう, 一生いっしょう and a cheerful slang word for best friends.

How do you say "forever" in Japanese?

What is 永遠えいえん?

永遠えいえん (えいえん) is "eternity", and 永遠えいえんに is "forever". It is a big, emotional word, at home in songs, poems, vows and fantasy.

永遠えいえんに愛いとしてる。 — I'll love you forever. (casual, a lyric-style declaration) 永遠えいえんの命いのちなんてない。 — There's no such thing as eternal life. (neutral, philosophical)

The two kanji mean "long-lasting" and "far". 永遠えいえん sounds sincere and dramatic. In daily conversation, it can sound a bit theatrical, which is exactly why songs love it.

What is ずっと?

ずっと means "the whole time, all along, forever", and it is the natural everyday "forever".

ずっと一緒いっしょにいようね。 — Let's stay together forever. (casual, warm) ずっと友ともだちだよ。 — We'll always be friends. (casual)

ずっと also covers the past and present: ずっと待まってた, "I've been waiting all this time". So it is less about eternity and more about something continuing without a break. It also means "by far" in comparisons: こっちのほうがずっといい, "this one is far better".

What is いつまでも?

いつまでも means "for as long as it lasts, forever", with a gentle, hopeful feeling.

いつまでもお元気げんきでいてください。 — Please stay well forever. (polite, a kind wish to an older person) いつまでも忘わすれないよ。 — I'll never forget, no matter how long. (casual)

いつまでもお元気げんきで is a lovely phrase for farewell cards and messages to grandparents and teachers. Our post on always in Japanese covers いつも, its everyday cousin.

Beyond the basics

What is 永久えいきゅう?

永久えいきゅう (えいきゅう) is "permanent", a more technical, practical word than 永遠えいえん.

永久歯えいきゅうし — permanent teeth (neutral, dentistry) このデータは永久保存版えいきゅうほぞんばんだ。 — This is a keeper; save it forever. (casual, a common joke about something worth keeping)

永久えいきゅう is used in rules, science and products: 永久保存えいきゅうほぞん (permanent storage), 永久えいきゅう凍土とうど (permafrost). It has less poetry than 永遠えいえん, but it says the thing really lasts.

How is 一生いっしょう different?

一生いっしょう (いっしょう) is "for the rest of my life", tied to one person's lifetime.

一生いっしょう忘わすれない。 — I won't forget this as long as I live. (casual, emotional)

永遠えいえん is beyond time; 一生いっしょう is the span of your life. 一生いっしょう also turns up in the famous phrase 一生いっしょうのお願ねがい ("the request of a lifetime").

What do people say at weddings?

末永すえながく (すえながく), "for a long time to come", is the polite "forever" of weddings and long relationships.

末永すえながくお幸しあわせに。 — May you be happy forever. (polite, the standard wedding wish) 末永すえながくよろしくお願ねがいします。 — I hope we'll be together for a long, long time. (polite, said by a newlywed couple or a new long-term partner)

末まつ means "end, future" and 長ながく means "long". 末永すえながくお幸しあわせに is the phrase to write in a wedding card, much more natural than 永遠えいえんに幸しあわせに. Businesses also use 末永すえながく for long customer relationships. Our post on congratulations has more wedding phrases.

How do you say "until I die"?

死しぬまで (しぬまで), "until I die", is a strong, casual "forever", often half-joking.

この味あじは死しぬまで忘わすれない。 — I'll never forget this taste until the day I die. (casual, exaggerating)

It is the same idea as 一生いっしょう, but more dramatic. Use it for food, music and memories you love.

What is ズッ友とも?

ズッ友とも (ずっとも) is slang for "friends forever", from ずっと友ともだち. It is cute and a little dated, popular among teens in the 2010s.

私わたしたちズッ友ともだよね! — We're friends forever, right? (very casual, playful)

It is the Japanese "BFF". Using it today can sound a bit nostalgic or ironic, which is part of its charm.

What is 永遠えいえんの17歳さい?

永遠えいえんの17歳さい, "eternally 17", is a playful line some celebrities use when asked their age.

年齢ねんれいは永遠えいえんの17歳さいです。 — My age? Eternally seventeen. (a playful dodge)

It is a well-known joke in entertainment, a cheerful way to avoid answering. Our post on saying your age has the serious version.

How does "forever" appear in anime and songs?

永遠えいえん dominates lyrics; ずっと dominates dialogue.

ずっとそばにいるから。 — I'll always be by your side. (casual, a classic comforting line)

If you read anime song titles, you will see 永遠えいえん, とわ (an old, poetic reading of 永遠えいえん) and 永久えいきゅう (sometimes read とわ too). In the actual scenes, characters say ずっと.

Common mistakes

  • Using 永遠えいえんに in everyday promises. It can sound like a song. ずっと is natural.
  • Thinking ずっと only means "forever". It also means "all along" and "by far".
  • Using 永久えいきゅう in love songs. It sounds technical, like a warranty. 永遠えいえん fits better.
  • Reading 永遠えいえん as えいとお. It is えいえん.
  • Using ズッ友とも in formal writing. It is playful slang.

Quick comparison

Word Reading Meaning Feel
永遠えいえんに えいえんに forever, eternally grand, lyrical
ずっと ずっと the whole time, forever everyday
いつまでも いつまでも for as long as it lasts gentle, hopeful
永久えいきゅう えいきゅう permanent technical
一生いっしょう いっしょう for the rest of my life personal, emotional
ズッ友とも ずっとも friends forever slang

Practice

Try each answer yourself before opening it. Questions 2 and 3 are a pair: the grand forever and the everyday forever.

1. What is "eternity" in Japanese?

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永遠えいえん (えいえん) — 永遠えいえんに is "forever".

2. A love song's chorus: "I'll love you forever." Which word fits best?

Show answer

永遠えいえんに愛いとしてる — grand and lyrical.

3. Casually to your partner: "Let's stay together forever." Which word sounds natural?

Show answer

ずっと一緒いっしょにいようね — ずっと is the everyday forever. This is the pair to question 2.

4. Say "I've been waiting all this time" casually.

Show answer

ずっと待まってた — ずっと also means "all along".

5. Write a kind wish to your teacher: "Please stay well forever."

Show answer

いつまでもお元気げんきでいてください — gentle and polite.

6. What are permanent teeth?

Show answer

永久歯えいきゅうし (えいきゅうし) — 永久えいきゅう is the technical "permanent".

7. Say "I won't forget this as long as I live."

Show answer

一生いっしょう忘わすれない — 一生いっしょう is your lifetime.

8. What is the slang for "friends forever"?

Show answer

ズッ友とも (ずっとも) — from ずっと友ともだち.

9. What does こっちのほうがずっといい mean?

Show answer

This one is far better. — ずっと means "by far" in comparisons.

10. How is 永遠えいえん read in old-style poetry and some song titles?

Show answer

とわ — a poetic reading.

Swap 永遠えいえん for ずっと when you make a promise in a trial lesson, and try ズッ友とも on a close friend.

FAQ

What is the hiragana for forever? えいえん for 永遠えいえん. The everyday word ずっと is already hiragana.

What is the difference between 永遠えいえん and 永久えいきゅう? 永遠えいえん is emotional and poetic. 永久えいきゅう is practical and technical, like permanent storage or permanent teeth.

What does とわ mean? とわ is an old, poetic reading for 永遠えいえん or 永久えいきゅう, "eternity". It appears in songs, names and titles.

How do you say "best friends forever"? ずっと友ともだち, or the slang ズッ友とも. 親友しんゆう (しんゆう) is "best friend".

Is ずっと always positive? No. It just means "the whole time": ずっと雨あめだった, "it rained the whole time".

How do you say "forever young"? いつまでも若わかく, "young forever", is natural. In song titles, 永遠えいえんに若わかく is also used.

Vocabulary from this article

Tap the block to select all of it, then copy. In Anki: File → Import, note type Basic, separator Tab — the first column becomes the front, the second the back.

永遠	えいえん — eternity
永遠に	えいえんに — forever
ずっと	ずっと — the whole time; forever; by far
いつまでも	いつまでも — for as long as it lasts
永久	えいきゅう — permanent
永久歯	えいきゅうし — permanent teeth
永久保存	えいきゅうほぞん — permanent storage
一生	いっしょう — for the rest of one's life
ズッ友	ズッとも — friends forever (slang)
とわ	とわ — eternity (poetic)
一緒に	いっしょに — together
親友	しんゆう — best friend
末永く	すえながく — for a long time to come
死ぬまで	しぬまで — until I die

I'm Yuuki, a Japanese teacher based in Tokyo. I've taught on italki as a Top 1% teacher and watched over 1,500 anime, so most of the example sentences on this blog come from lines I've actually heard students ask about. Swapping 永遠えいえん for ずっと is one of the easiest changes that makes a learner's Japanese sound like conversation instead of a song. For practice with feedback, Book a trial lesson · $13, or work through Japanese practice exercises first.

Sources: the author's own lessons and standard Japanese dictionaries.

More drills like the ones above, plus a timed JLPT-style mock test: Practice · N4 · Read something at this level: JLPT N4 stories with audio

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