Credit cards are the default requirement mainly because rental companies use the card to place a security hold and because a credit card carries built-in protections the company relies on. Debit cards can often be used instead, but almost always with additional conditions: a larger security deposit, a required credit or background check at the counter, and sometimes proof of a return flight or onward travel.
Prepaid cards and cash are accepted far less often and usually only at specific rental locations, so if that's your only payment option, it's worth confirming directly with the rental branch before you arrive, not just checking the general company policy online.
The security deposit for a debit card rental is typically higher than a credit card hold, and it can take several business days longer to be released back to your account after you return the car — worth planning for if you're on a tight budget during your trip.
If you rent regularly without a credit card, building a rental history with the same company can help — some rental companies loosen debit card restrictions for repeat customers with a clean rental record.
