way back when

Adjective

idiomatic

(idiomatic) At a time in the distant past.

Japanese Meaning

はるか昔のある時期 / 昔々の時代 / とても遠い昔 / ずっと昔の事

We visited the way back when town during our summer trip.

私たちは夏の旅行で遠い昔の町を訪れました。

Sense（1）

(idiomatic) At a time in the distant past.

Even Warren Buffett was skeptical of Amazon way back when.