Barracuda are not super picky and they will bite well throughout the day. You can catch them easily from morning through evening and they bite well at night as well. If you are fishing inshore waters, the big thing that will dictate the bite is going to be the tidal changes. Avoid the slack tides as the bite is usually poor during this time. The moving water on the incoming tide or outgoing tide are both good times to fish and they bite well during the low tide and high tide.
If you can get the right tide for the area you are fishing with an early morning or late evening, the bite will usually be better. However, if you’re looking for some action and you want to catch barracuda, you don’t have to fish those peak low light conditions to catch them. They will bite all day long.