The natural Korean way to say “At what time will your mother pick you up?” is 엄마가 몇 시에 데리러 와요?

Slightly more polite

You can also say 어머니가 몇 시에 데리러 오세요? if you want a more respectful tone.

Word-by-word sense

  • 몇 시에 = at what time.
  • 데리러 오다 = to come pick someone up.
  • 엄마 / 어머니 = mom / mother, with 어머니 sounding more formal.

Useful variation

If you want to ask very naturally in conversation, you can also say:

  • 엄마가 언제 데리러 와요? = When will your mom pick you up?

TL;DR: 엄마가 몇 시에 데리러 와요? is the simplest, most natural version.