"What time are we going?"

[SheridanZhoy]

Is "Ne zaman gidiyoruz" correct?

[Selcen_Ozturk]

ne zaman is "when", so it is not necessarily asking for the exact time. Therefore, no.

[gunce1]

Ne zaman gidiyoruz? Altıda gidiyoruz. I think

[MarionNot]

Why is it wrong to add "biz" here, as in "Saat kaçta biz gidiyoruz"?

[AlexinNotTurkey]

Normally "biz" would go at the beginning of the sentence. Yours isn't wrong though and it has been added as an alternate.