How can I stop same day arrivals?

Sorry, we can't find anything

If you want to disallow same day reservations for direct bookers go to Revenue -> Rates & Restrictions -> Show Advanced Options. Enter 1 (or a higher number if required) in the 'Days before arrival date' field.
If you want to disallow same day reservations from OTAs this is managed in Revenue -> Distribution -> View Distribution List. Edit the property integration groups in questions and update the field 'Days before arrival date'

;