Unless these are in excellent condition and suitable for reuse, they should be thrown out.
Swimwear cannot be recycled. But they can be passed on for reuse through Cloop bins.
Please only put clean, usable swimwear in these bins. Any swimwear that is stained, with holes or damaged elastic does not below here.
There may be people interested in 2nd hand swimwear in good condition, particularly for children.
You may even be able to sell them online.
Like underwear, because of hygiene issues, most charities will not take swimwear unless they are unused and still in the original packaging. However some people online may be more flexible. Loose fitting clothing, like board shorts, are likely to have more demand.