Casual wear is ok, but would recommend tshirt or beach dress cover up. It's a place where you can dress up or be casual, being on the tourist strip they expect casual dress or should say they are used to it. There is also a patio outside as well.
It's an upscale place.
As noted in Katshot's answer that is a heck of a walk from the beach. However, dress code is casual at the Columbia. Swimwear... Not too sure about that.
Not sure about the question. Since the place is not on the beach, I'll assume you're asking about the dress code. I would say they wouldn't allow patrons in swimwear.
Thanks! Your answer is awaiting moderation.