N3 Time, Sequences, and Change

~たとたん: meaning, usage and examples

~たとたん means: the moment... / right after...

Updated 9 November 2026 · By the My Senpai team · Spotted a mistake? Tell us

Examples

1. ベッドに入はいったとたん、寝ねてしまった。

   I fell asleep right after getting in bed.

2. ドアを開あけたとたん、猫ねこが飛とび出だしてきた。

   The moment I opened the door, the cat jumped out.

3. 電車でんしゃを降おりたとたん、財布さいふがないことに気きづきました。

   The moment I got off the train, I noticed my wallet was gone.

4. 先生せんせいが教室きょうしつを出でたとたん、学生がくせいたちが話はなし始はじめました。

   The moment the teacher left the classroom, the students started talking.

When to use it

Use たとたん to say that something happened immediately after an action, at that very moment: "the moment X, Y." 外そとに出でたとたん、雨あめが降ふり出だした means "The moment I stepped outside, it started raining." The second event is usually something the speaker did not expect or control.

Nuance

The second clause reports something that already happened, so it is in the past tense and cannot be a command, intention or invitation (家いえに着ついたとたん、電話でんわしよう is wrong). The feeling is surprise at how suddenly the second thing happened. It is common in conversation and stories.

Compare

と同時どうじに is a neutral "at the same time" and allows planned events: ベルが鳴なると同時どうじに試験しけんが始はじまった. てすぐ means "right after" and allows your own intentional actions: 家いえに帰かえってすぐ宿題しゅくだいをした. たとたん adds suddenness and surprise: 立たち上あがったとたん、頭あたまが痛いたくなった.

Tip: If the second part is your own planned action, use てすぐ, not たとたん. たとたん is for what happened to you, not what you decided to do.