This seems like an obvious question but im just double checking.

Im planning to apply for a card (Hilton Reserve) that offers a $100 statement credit when used at a Hilton property "within the first 3 months of account opening".

My question is if I apply today and get instant approval today, is the Account opening date November 13th?

Or is the account opening date after I receive the card and call and activate the account (which could be 10 days from now....or more if I don't call right away).

Im planning a Hilton stay at the end of Feb and either have to wait for the very end of the month to apply and risk the $100 statement credit offer being pulled (which has happened from time to time).

Thanks in advance.

The opening date will not change just because you don't activate the card. What the actual date is I'm not sure but its likely the day you are approved or the next day.

From what I have read, it is usually the date you apply. But I also have seen Chase give me more than 90 days. So, YMMV.
To be safe, you should wait until you apply for your card.

With Citi (which is what you're asking about here), It is definitely either the day you're approved (which could be the day you apply if you're instantly approved), or at most a day or two later (but don't even count on that). So if you know you won't have that Hilton stay before late February (and count the check-out date, not the check-in date, to be extra safe!), I recommend not applying until early December to have some buffer time (in case Citi counts days slighty wrong, as they've been known to do, or in case your plans are slightly delayed, say due to winter weather).

Besides the three months for the credit, keep in mind that the free weekend night certificates (that Hilton Reserve card offers as the main singup bonus) expire after a year, so that's the other timing to factor in.

Thank you....ill play it safe with some buffer since its Citi....

Re weekend credits- prob the best part of the deal...I wont forget to use them...