～際(に)
At the time of an event in formal situations
You’ll be able to refer to the occasion when something happens in instructions, notices, and other formal contexts.
キャンプ場をご利用の際は、こちらで受付をしてください。
kyanpujou o goriyou no sai wa, kochira de uketsuke o shite kudasai.
What do you think this sentence means?
When using the campsite, please check in here.
On the occasion of or when
～際(に) is a formal version of “when” or “on the occasion of.” It appears often in notices, business language, and polite instructions. It is less natural than ～とき in casual conversation.
地震の際は、エレベーターを使わないでください。
jishin no sai wa, erebeetaa o tsukawanaide kudasai.
In the event of an earthquake, do not use the elevator.
電車を降りる際は、忘れ物に気をつけてください。
densha o oriru sai wa, wasuremono ni ki o tsukete kudasai.
When getting off the train, please take care not to leave anything behind.
Use it in formal instructions
Use noun + の際(に) or dictionary/past verb + 際(に). The past form can mean “when doing/when one did,” not necessarily that the action is fully over.
お申し込みの際に、住所が必要です。
omoushikomi no sai ni, juusho ga hitsuyou desu.
An address is required when applying.
お問い合わせの際は、会員番号をお知らせください。
otoiawase no sai wa, kaiin bangou o oshirase kudasai.
When contacting us, please give your membership number.
チェックアウトする際に、鍵をフロントに返してください。
chekkuauto suru sai ni, kagi o furonto ni kaeshite kudasai.
When you check out, please return the key to the front desk.
お支払いの際に、ポイントカードをお出しください。
oshiharai no sai ni, pointo kaado o odashi kudasai.
Please show your point card when you pay.
7 more examples in the grammar path — free for a limited time.