It seems like a cash deposit in a USAA ATM will be available the second business day after the deposit is made. (for example if you deposit on Monday it will be available Wednesday).
If it is a non-USAA ATM it will be the fifth business day after (which may span a weekend and be a really long wait).
Here is where I got that info:
I think you'll find USAA is a great bank, but not having lots of local branches takes a bit of getting used to. I don't mind it at all but I've been banking at USAA for more than 20 years now.
Thank you for your comment regarding your cash deposit. Due to the nature of your post, a service specialist would be in the best position to address your concern. They would be able to review the account in more detail to determine what may be the reason for the delayed availability of funds. As such, we ask that you please click here to provide us with additional detail and your member information. You can also reach a service specialist at 1-800-531-8722.