There is a board at the beach that say no swimming if the red flag is up. There have been many death due to drowing at this beach so beware and don't go swimming during the monsson season from late November to end March.
From end of September to January is the monsoon season for East Coast of Malaysia. Therefore, when planning your trip to Kuantan, try to avoid this period as roads will not be accessible during floods.
Some hotels will even offer your a free night of stay should the it rains consecutively for two days.
Beaches in Kuantan have a flag post erected. At normal times, the red flag will be at half mast. This indicates that the beach is safe for swimmers / surfers. On the other hand, if you spot a fully raised red flag flying, you better refrain from the beach. The tides & waves will be high & dangerous for any beach activities.
At night especially, ensure that females travel with someone else. I made the mistake of leaving a bar on my own one night. I was propositioned all the way home. Although nothing happened I felt extremely unsafe, with large groups of males following me.