Hi Clare!
Thank you for bringing your question to the Disney Parks Moms Panel. There is an endless amount of delightfully dreadful fun to be had at
Oogie Boogie Bash- A Disney Halloween Party and I'm so excited for you to experience this to the fullest by dressing up in costume!
With your special event ticket, you can enter
Disney California Adventure Park up to four hours prior to the party, so get ready to enjoy all the not-so-scary fun from 2 PM on! You will be able to enter with your costume at this time and will not need to worry about changing after the party begins. Please just make sure your costume adheres to the appropriate guidelines. For Guests aged 14 and older this includes the requirement that costumes must be family-friendly and may not be obstructive, offensive, objectionable or violent. Any item that resembles a weapon or contains sharp or pointed objects is prohibited. For safety purposes, layered or prop costumes are discouraged and costumes that reach or drag on the ground are prohibited. You are free to rock any head ware incorporated into your costume, but your face must be visible. While I've truly seen some amazing and impressive costumes attending Halloween events, please remember that Guests can not pose for pictures or sign autographs as we don't want to confuse little mouseketeers!
I hope this is helpful in planning your quickly approaching visit! Let us know if we can help in any other way.
-Lindsey