How early should you arrive to a convention?

I recommend showing up 30 minutes to an hour before the exhibit floor opens. 

Now for the long answer. This is a question asked in a lot groups, chats, and forums. And its a question that has a difficult answer because it's usually answered with questions. There's no clear answer but in this blog I am to answer this question as detailed as possible so you can make your own decision on how early to show up to convention.

30 minutes before the convention opens or an hour before the floor opens is what I recommend for people who do want to show early. These are two different answers because some conventions have two different opening times. WonderCon and Anime Expo both open up the building before the exhibit floor and panels begin. So you will have to wait in two different lines. This is assuming you already have a ticket in hand.

One hour before ticketing window or registration window opens is my recommendation if you want to buy a ticket on site or need to pick up your ticket onsite. This extra time is going to be needed in case the ticketing window isn't set up properly. Some conventions  like SDCC and Anime Expo allow badge pick ups the day before and I recommend to take advantage of that if able. Nowadays a lot of conventions do ship out badges if purchased before a certain date.

Two hours before a convention opens is what I recommend if you want an exclusive item sold from a smaller booth or want to get good seats to a panel with medium demand happening first in the convention day. I love getting convention exclusives so I fall in this category. I'll make getting exclusives its own blog post. Some exclusives will have an online raffle portion like Funko does so no early line up is needed. Lots of conventions have an app where people can favorite panels, use that to know if a panel is in demand.

4 to 8 hours before a convention opens if you want to be in the first row or guarantee a non raffle exclusive. I recommend lining up with someone and be prepared for the wait. Get yourself a foldable chair and some snacks and water and be bundled up. This is also the time to line up if you want to get an autograph that requires you to line up. 

There are some events and conventions that require 12+ hours of waiting. While this sounds like a long time, if you have a group that rotates than it becomes more manageable. For example Hall H from SDCC allows one person to wait for 5 but you start waiting the day before. The way Anime Expo does autographs allow people to wait the night before. In previous years where there were idols signing or voice actors signing people have camped started the evening before. 

I hope this answers your question on how early should you arrive to a convention. It really depends on you and what you'd like to do. You also do not have to show up early, you can show up an hour late into a convention and walk in.