I have some plain black chunky trainers that would be good - I don't like normal trainers with jeans or smarter clothes.
Slim 7/8 trousers and a top/blouse
Sandals that you can walk in, if it will be hot.
I'm sure dresses will be fine too, if not too smart/structured.
I recently went to a conference in a hot European city and had a plain looseish midi dress, loose blouse and slim cropped trousers and a slightly smarter dress with a light cardigan (indoor air conditioning was fierce) on the day I was speaking.
I wore a combination of the aforementioned trainers and sandals, which were good even though we went on two walking tours and the trek to and from the airport added up to about 50k steps in 3 days.
There was no specified dress code and some people were quite casual and some quite formal, so as 'business casual' is open to interpretation, I'm sure that as long as you don't wear a sack or ripped jeans or a cocktail dress or dinner jacket at the other end of the spectrum, you'll be fine and feel appropriately dressed.