Of course you need a bathing suit and towel. Most of us have the polyester training suits because they last very well with the chlorine. Many of the men wear the 'bike shorts' type of suit and most of the women wear a t-back one-piece suit.
I would recommend wearing flip flops to protect your feet on deck and in the showers bring a toiletry kit with shampoo/conditioner/body wash to wash up after our practices. (We always smell like chlorine but a little shower gel smell on top of it is nice!)
Most of us wear goggles and a cap. The silicone caps last longer. Goggles are a matter of personal choice and fit. Some swimmers wear their triathlon goggles and some wear the smaller racing goggles. Whatever works for you! Some people like nose clips, some don't. It's all what you like to use!
We do a fair number of kick sets with fins. You'll see every type of fin in the pool, so again, this is a personal preference. The most popular seems to be these Speedo fins (not too long or short). Some people wear socks with the fins because of blisters. You'll find what works for you.
We also do some pull sets where we use pull buoys. The popular pull buoys are these Speedo ones but many of us still use the 'old-school' ones with two foam cylinders strapped together. Again, it's a personal preference.
Sometimes (not that frequently) we use paddles. There are a ton of different kinds but it seems that these Speedo paddles are most common.
None of this equipment is mandatory but it's an outline of some of the things you'll see on deck!
As a team, we get a 20% discount off all regular priced merchandise at the Splashables website. Let them know that you swim with the Milton Masters and they will apply it to your purchase. Happy swimming!