Can you use anything else except tampons when going swiming?

Yes, as well as different types of tampons you can use menstrual cups, softcups or diaphragms as sanitary protection while swimming on your period.

Menstrual cups are the best option.

Cups are internal like tampons but they are far safer than tampons so no risk of TSS, infections or dioxin - this also means that unlike tampons cups can be worn for 12 hours including before your period and with light flow so more convenient. Menstrual cups are also better for swimming because where as tampons can increase cramps cups reduce cramps, cups don't absorb water, nothing shows outside of your body while wearing a cup, and menstrual cups don't leak like tampons.

You cannot use pads when swimming.

In the water the pads become saturated with water, even if they didn't blood wouldn't flow down into the pad anyway so would make it into the water, also if you use disposable pads these would come unstuck and fall apart so make a big mess.