Hi,
You can find all HK public swimming pools and opening times in this website:
www.lcsd.gov.hk/.../swim-location-hk.php
Please bear in mind though that public swimming pools in HK typically only allocate 1 (sometimes 2) lanes for lap swimming and it can get a little crowded. It thus make it difficult sometimes to practice.
Having said that my favourite pool is Victoria Park Swimming Pool - a newly renovated complex with two indoor swimming pools.
I hope this info helps.
