I thought there was an error as there wasn't the option of using "costumes". I would never say "bathing suits" in the UK. Perhaps "swim suits".
Beach clothes are Bigdey Hof (like a beach dress)
Bigdey Yam are always for swimming. You would not say "beach clothes" in English when talking about what you wear while swimming.
Here's another example of an Israeli Hebrew speaker using "bigdei" in a similar phrase/collocation: בגדי השבת. https://forvo.com/word/he/%D7%91%D7%92%D7%93%D7%99_%D7%94%D7%A9%D7%91%D7%AA/#he