Hawzah News Agency – Q: What rule applies to someone who immerses himself in water wearing waterproof clothing such as a diving suit which does not allow the body to become wet?

A: If the clothing has close contact with his head, it is problematic to say his fast is valid. Hence, as an obligatory caution he should perform its qaḍā’.

Source: https://www.leader.ir/en/book/32/Practical-Laws-of-Islam