How to tell them apart
際（に） is a formal version of とき that marks when something happens, as in 旅行の際に and 来日した際に. に当たって marks facing a major formal occasion and doing an intentional action for it, as in 開業に当たって挨拶する. 際 can describe past moments, while に当たって looks forward to the occasion and needs a volitional main clause about greeting, preparation or resolve.
- 際（に） Use 際（に） to say at the time when something happens in formal style.
- に当たって/当たり Use に当たって/当たり to say on the occasion of facing a major formal event and doing something intentional for it.
| Grammar point | Meaning | JLPT level |
|---|---|---|
| 際（に） ni | at the time of, on the occasion of (formal usage) | N3 |
| に当たって/当たり ni tatte tari | at the time of a particular event or occasion | N2 |
際（に） ni
at the time of, on the occasion of (formal usage)
際(に) means at the time of or on the occasion of, used to mark a specific moment or opportunity when something happens. It follows nouns with の, as in 面接の際に, and verbs in dictionary form for future events or た form for past events, as in 申し込む際に or 引っ越した際に. It is formal and common in announcements, instructions, and business writing, and に is often optional without much change in meaning.
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海外へ旅行する際には、通常、パスポートが必要である。
When you travel abroad, you usually need a passport.
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申し込む際に身分証が必要です。
You need ID when you apply.
に当たって/当たり ni tatte tari
at the time of a particular event or occasion
にあたって and its more formal written variant にあたり mean on the occasion of or at the time of an important event. They are used to introduce a speech, thanks, greeting, or decision connected with occasions like 開店, 卒業, or 就任. They attach to a noun, often a verbal noun expressing an event, as in 開店にあたり or 入学にあたって. The expression is formal and common in speeches and announcements, so it does not suit casual everyday events.
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開店にあたり、心からお礼を言います。
On the occasion of our opening, I offer my heartfelt thanks.
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卒業にあたり、先生に感謝を伝えた。
Upon graduation, I expressed my gratitude to my teacher.
際（に） and に当たって/当たり are JLPT N3–N2 grammar points that Japanese learners often mix up. This page compares them side by side on meanings, usage and example sentences, so you can tell them apart.