Equipment for swim team can be confusing. At a basic level, your swimmer needs a suit (one piece for girls, trunks or briefs for boys) tight fitting suits work best but if your swimmer prefers something looser that works too. A pair of good goggles that fit them well and are comfortable, and a swim camp (especially for athletes with long hair). There are two kinds of swim caps, silicone and latex. Both work but silicone is preferred by most swimmers on the Seals.
There are many places to buy equipment online. One place to start looking is Swim Outlet. However, there are many other options as well.
Ask Vivian what other equipment you may need. We supply kick boards, pull buoys, and fins (you may need to get fins if we don't have your size).