As soon as possible; at the earliest possible time — used to request or instruct that something be done promptly.
資料が届き次第、できる限り早くご連絡します。
As soon as the materials arrive, I will contact you as quickly as possible.
問題が発生したら、できる限り早く上司に報告してください。
If a problem occurs, report it to your supervisor as soon as possible.
できる限り早く出発したいので、準備を急ごう。
I want to leave as soon as possible, so let's hurry our preparations.