There is no official waiting list for the 9/11 memorial — but anyone who wants to visit the site had better act fast.

Online reservations, offered at 911memorial.org, are being snapped up quickly.

As of late yesterday, only a few time slots remained for September.

There are a limited number of “same day” tickets available, but they are subject to availability. Visitors can obtain same-day passes at the Preview Site at 20 Vesey St.

About 7,000 people from 30 countries were issued tickets for opening day yesterday, officials reported.