An idiomatic expression meaning 'we'll deal with it when the time comes' — don't worry about it now; similar to 'it will work out.'
就職できるか不安だけど、まあその時はその時だよ。
I'm worried about getting a job, but well — we'll deal with it when the time comes.
もし雨が降ったらどうする？──その時はその時で考えよう。
What if it rains? — We'll think about it when that happens.
お金が足りないかもしれないが、その時はその時だ。まずは挑戦しよう。
We might not have enough money, but we'll cross that bridge when we come to it. First, let's try.