Yes you can. We did it last year. There's a separate line at check in for people that have already done it online & your package is already prepared for you. We did it last year & didn't think it was worth it as by the time we checked in it wasn't busy (it was 5 pm in Sept) & there wasn't a line for either online or non-online. It still took us a while to check in anyways. Maybe at a really busy time it may save you time. I have heard though that since it's become so popular the line up for online check-in is longer than for people that didn't check in online.