You do not need a special stoma bag to go swimming, though some ostomates like to wear a smaller bag or a stoma cap whilst they are in the water.
If you wear a stoma bag with a filter, use the filter cover (sticky patches normally supplied by the manufacturer in your box of stoma bags) so it does not get ruined by the water.
Some stoma bags have covers particularly suited to swimming (and showering and bathing). Our Aura range of flushable, colostomy, ileostomy and urostomy bags, for instance, features a soft cover made from a special rapid drying fabric – it really is like water off a duck’s back. You don’t have to worry about wet patches or discomfort; when you get out of the water, simply pat the bag down gently with a towel. This fabric can help with perspiration build up as well.