If you use your debit card to make a purchase from a vendor, or withdraw cash from an ATM, the transaction amount will reduce your available Checking balance immediately.
Withdrawals to your connected funding account generally take 1 to 2 business days to fully complete.
In some situations, withdrawals may take longer. An example of this would be if you make a deposit and then withdraw it to your connected funding account immediately, which could lead to your withdrawal taking up to 6 business days to be fully received.
See the Transaction Timeline Table