I am planning on seeing that same movie this weekend. I would wear shorts or capris over my swim suit. Wear a short-sleeve t-shirt and sandals. Have fun!
I'm doing the same thing this saturday just with my bf haha thats weird. But I'm probably just gonna wear like a cute/casual looking dress with my bathing suit under it and some sandals. That way it won't be so complicated. Hope you have fun!
Wear something comfortable because you have a long day ahead of you. Maybe shorts and two different cute tops. Nothing that will be hard to change out of for your friends birthday party. Comfort will make your over all mood SO much better, trust me.
You should wear your swimsuit, and wear some kind of long sundress you can just pull on. Pick a fun print, for a birthday party! A nice white sun hat would be a nice touch, too.