As far as I know, the team haven’t told us this yet (they may reply today of course) I’m afraid.
There’s a few things that’re worth bearing in mind here -
- If you don’t have the funds in your account, the overdraft will simply bounce & you won’t be charged any fees as a result (source)
- Monzo will know 24 hours before the DD is due to be taken so they should be able to give you a heads up. But that feature hasn’t been announced yet.
- Monzo does list your scheduled payments in the current account app so you’ll alway have that for your reference -
PS - in case there’s anything else that you’re wondering, you might find the answer in this Wiki which lists everything that we know about the current accounts & debit cards so far.