Answer:
If you mean you expect your period and you want to go swimming then no.
Contact with liquid (the pool water) makes the pad expand and lose its ability to absorb your discharge.
The water also makes the adhesive on the pantyliner weaker...so it may not stay attached for long.
You are safer using a tampon when swimming during your period.
However if you don't intend to actually swim/have your swimsuit come in contact with water then this should be ok.